Talking back to nativism

Dana Millbank is a political columnist for the Washington Post. He broke out of his political mold on April 7, 2023 to write an article about gardening published by the Post, which repeats every myth of the nativist ideology. 

A team of dismayed critics of invasion biology has responded to excerpts of Millbank’s column:

  • Marlene A. Condon is a garden writer based in Virginia and the author of The Nature Friendly Garden. She has a degree in physics. Her entire critique of Millbank’s column is available on her website.  Her comments address the reader.
  • Carol Reese is a retired Extension Horticulture Specialist who conducted her 27 year career from the University of Tennessee’s West Tennessee AgResearch and Education Center in Jackson, where a large and diverse display garden gave her the opportunity to observe biodiversity in action on an enormous range of plant species from other parts of the world. She describes herself as a farm raised country girl tomboy who has looked at the natural world in hundreds of settings and landscapes, natural and manmade, and read countless books and articles. She has written for several magazines, newspapers, articles for Garden Rant as well as university publications.  Her speaking engagements around the country have allowed her to engage with many other green industry professionals. Dana Millbank’s column prompted her to email him directly with her concerns, directly addressing some of his assertions. I publish some excerpts here from her emails sent directly to Millbank.
  • Conservation Sense and Nonsense is the webmaster of this website.  I have studied invasion biology and the native plant movement it spawned for over 25 years. I’ve watched forests of healthy, non-native trees in California be destroyed and replaced by weedy grassland.  I have used what I have learned to advocate for a less destructive approach to restoration, a word I am reluctant to use to describe projects that use herbicides to eradicate harmless plants and trees. My comments are addressed to the reader.

What follows are excerpts from Dana Millbank’s column with responses from Marlene Condon, Carol Reese, and Conservation Sense and Nonsense, just three of many skeptics of invasion biology.  To summarize the point of our criticism:

  • Insects are not dependent on native plants.  They are just as likely to use related non-native plants in the same genus or even plant family with similar chemical properties and nutritional value. 
  • While some non-native plants have potential to be harmful, many are beneficial. There are pros and cons to both native and non-native plants and that judgment varies from one animal species to another, including humans. For example, we don’t like mosquitoes, but they are important food for bats and birds.  
  • All plants, whether native or non-native convert carbon dioxide to oxygen and store carbon. Destroying them contributes to greenhouse gases causing climate change.
  • When the climate changes, vegetation must also change.  Many non-native plants are better adapted to current climate and environmental conditions in disturbed ecosystems.

Conservation Sense and Nonsense


“I’m no genius about genuses, but your garden is killing the Earth”
By Dana Millbank
Washington Post, April 7, 2023

Millbank:  I did almost everything wrong.

ReeseI’m so sorry you thought this!

Millbank:  For 20 years, I found the latest, greatest horticultural marvels at garden centers and planted them in my yard: sunny knock-out roses, encore azaleas, merlot redbud, summer snowflake viburnum, genie magnolia, firepower nandina.

In between them flowed my lush, deep-green lawn. I hauled sod directly from the farm and rolled it out in neat rows. I core-aerated, I conditioned, I thatched, I overseeded, I fertilized. I weeded by hand, protecting each prized blade of tall fescue from crabgrass and clover.

In this season, a symphony of color performs in my yard. The fading daffodils, cherry blossoms, saucer magnolias, hyacinths and camellias meet the arriving tulips, lilacs, creeping phlox and azaleas, with the promise of rhododendrons, peonies, hydrangeas, day lilies and roses to debut in the coming weeks.

But this year, the bloom is off the rose. And the hydrangea. And the rhododendron. And all the rest. It turns out I’ve been filling my yard with a mix of ecological junk food and horticultural terrorists.

Condon:  When Mr. Millbank posits that he’s “been filling his yard with a mix of ecological junk food and horticultural terrorists,” he’s channeling the kind of words Bringing Nature Home author Doug Tallamy loves to employ:  Biased expressions that implant negative images in the reader’s mind so he will become yet another minion of this scientist.  Nowadays you can’t read a garden or environmental column without being accosted with the same words or variations thereof, as if everyone has become a mouthpiece for Doug Tallamy, which I’ve never seen done more obviously than in this column by Dana Millbank. 

Conservation Sense and Nonsense:  Millbank’s lengthy list of “bad” plants in his garden paints with too broad a brush.  For example, instead of identifying a particular species of hydrangea and rhododendron, Millbank condemns an entire genus.  Both hydrangea and rhododendron genera have several native species within the genus.  Most (all?) species of phlox are also native to North America. 

Millbank:  When it comes to the world’s biodiversity crisis — as many as 1 million plant and animal species face near-term extinction because of habitat loss ― I am part of the problem. I’m sorry to say that if you have a typical urban or suburban landscape, your lawn and garden are also dooming the Earth.

Reese:  YIKES! This is pretty extreme, and dare I say inaccurate? No, home gardeners are part of the solution, no matter the plants in their garden. Doom will come from lack of diverse green space. Doom will come from climate warming as a result, as well as from pollution, tillage, factory farming and development.

Millbank:  I came to understand the magnitude of my offenses after enlisting in nature boot camp this spring. I’m in “basic training” with the state-sponsored Virginia Master Naturalist program. While others sleep in on rainy weekend mornings, my unit, the Arlington Regional Master Naturalists, has us plebes out in the wetlands distinguishing a yellow-bellied sap sucker from a pileated woodpecker.

I’m no genius with genuses, but I know a quercus from a kalmia, and because of my gardening experience, I began the program with confidence. Instead, I’ve discovered that all the backbreaking work I’ve done in my yard over the years has produced virtually nothing of ecological value — and some things that do actual harm.

A few of the shrubs I planted were invasive and known to escape into the wild. They crowd out native plants and threaten the entire ecosystem. Our local insects, which evolved to eat native plants, starve because they can’t eat the invasive plants or don’t recognize the invaders as food.

Anise swallowtail on non-native fennel. Courtesy urbanwildness.org “Papilio zelicaon, the anise swallowtail, typically has one to two generations in the mountains and foothills of California where it feeds on native apiaceous hosts. However, along the coast, in the San Francisco Bay Area and the urbanized south coastal plains and in the Central Valley, P. zelicaon feeds on introduced sweet fennel, Foeniculum vulgare, and produces four to six or more generations each year… the use of exotics has greatly extended the range of P. zelicaon in lowland California.” SD Graves and A Shapiro, “Exotics as host plants of the California butterfly fauna,” Biological Conservation, 2003

Reese:  It sounds so logical, but is sooo inaccurate. Ask any entomologist that has spent their careers “fighting pests” on valued crop or ornamental plants. Remember Pangea [when all continents were fused into one]? More recently, have you thought about the exchange of plants and animals across Berengia when we were still connected to Asia? We can trace those relationships/kinships of our plants to Asian/Eurasian plants now through DNA. They eventually differentiated into species (a continuum of change caused by climate and geologic pressures until we [Man] declare it as a different species, though biologically it is still basically the same nutritional makeup)

Condon also dissects Millbank’s statement: 

  • “They crowd out native plants and threaten the entire ecosystem.”  Read virtually any description of where you find so-called invasive plant species and you will find the word “disturbed.”  This tells you the soil profile has been negatively impacted by people, animals, or weather, and usually means the topsoil is gone.  Only very tough plants—known as colonizers—can grow in disturbed areas because the soil is nutrient-poor and is typically compacted.  Consequently, these areas may fill with a mix of native and nonnative plants, or mainly one or the other—but every single plant is a colonizer that is working to rehabilitate the land for the benefit of the native plants that require topsoil in which to grow.  “Invasiveness” is nothing more than a derogatory word used by people with contempt for alien-plant colonization.  Conclusions:  Alien plants can’t “crowd out” native plants because once the soil is disturbed and thus degraded, most of our native plants can’t grow there and thus are not there to be crowded out.  As for “threatening the entire ecosystem,” to the contrary, alien colonizers are helping to restore it.
  • “Our local insects, which evolved to eat native plants, starve because they can’t eat the invasive plants or don’t recognize the invaders as food.”  This oft-repeated distorted premise comes straight out of Bringing Nature Home, in which Doug Tallamy deceptively writes about “an excellent demonstration of how restricted a specialist’s [an insect with particular food preference] diet is.” Tallamy tells the story of Eastern Tent caterpillars on a cherry tee denuded of its own leaves but hosting a Japanese Honeysuckle vine.  He writes that the caterpillars didn’t recognize the honeysuckle as food (sound familiar?)  But, of course, they didn’t because this species of insect can only eat plants in the Rose Family, which does not include honeysuckle.  What Doug Tallamy doesn’t tell the reader is that the tent caterpillars could certainly have eaten the so-called invasive Multiflora Rose, which I’ve documented in the photo below.  Conclusion:  Native insects did not evolve to eat only local (native) plants, but rather can typically feed upon dozens, if not hundreds or thousands, of plants related to each other by family classification, even though they grow in other countries.
Tent caterpillar on multiflora rose.  Photo by Marlene Condon.

Millbank:  This in turn threatens our birds, amphibians, reptiles, rodents and others all the way up the food chain. Incredibly, nurseries still sell these nasties — without so much as a warning label.

Reese:  As I read, I also watch the many birds on my lawn, the fence lizards on my decks, the insects humming among the flowers in my diverse collection of native cultivars and introduced plants. 

Hummingbird in eucalyptus flower. Eucalyptus blooms from November to May. It is one of the few sources of nectar and pollen for birds and bees during the winter months when little else is blooming. Courtesy Melanie Hoffman
Eucalyptus leaf litter makes excellent camouflage for this garter snake. Courtesy Urban Wildness

Millbank:  Most of my other plants, including my beloved lawn, are ecological junk food.

Reese:  Now, now! Many (most) natives do not supply useful forage either. All plants supply some benefit. They provide shelter, create, improve and anchor soil, cleanse air and water, make oxygen and cool the planet. The plant must be judged on benefits versus detriments in each situation. If a nonnative plant is the only thing that will flourish in bombed out rubble, or contaminated soil, if it is providing many benefits, shall we rip it out because caterpillars won’t eat it? If we let it get established, will it ready the site for other species with more benefits to become established? Shall we get out of the way and let nature do what she does, which is heal herself?

Millbank:  The trees, shrubs and perennials are mostly “naturalized” plants from Asia or Europe or “cultivars,” human-made varieties of native plants bred to be extra showy or disease resistant but lacking genetic diversity or value to animals. I, like other gardeners I know, planted them after mistaking them for their native cousins. They’re not doing harm, but neither are they doing anything to arrest the spiral toward mass extinction.

Reese:  Please know that the most influential native plant botanical garden in the country (Mt. Cuba Center)  has trialed the cultivars of native plants for their ecological benefits and found as should be expected, that each cultivar must be judged on its own merits. Some are better than the straight native as in the coneflowers where ‘Fragrant Angel’ scored tops for pollinators and many others were very close to being as good as straight species. These cultivars were even better than the other species of Echinacea tested. BTW, I grow E. purpurea, pallida, paradoxa, tennesseensis and laevigata as well as many cultivars. Remember that cultivars should also be judged on not just nutritional value, but other factors that increase benefits, such as length of bloom period, numbers of blooms, drought resistance, heat tolerance, hardiness, ease of production (cost) and durability. Please ask to speak to Sam Hoadley there as he leads the research on beneficial cultivars and has completed and undertaken several studies of different native species. Great guy and great speaker. 

Please be aware that many cultivars originated as naturally occurring deviations in seedling populations, and as we know this actually diversifies the genetic pool, allowing Mother Nature to select the better form. We sometimes agree with her, and other times we may move along that diversifying form by crossing it with others that are demonstrating genetic variance. Logically, this actually furthers the cause of a broader genetic pool that can help in today’s crisis in showing which can cope and flourish.

Millbank:  To get a sense of my missteps, I asked Matt Bright, who runs the nonprofit Earth Sangha, a native-plant nursery in Fairfax County (and a lecturer on botany for my nature boot camp) to walk through my yard with me.

He took aim at my day lilies: “I would remove them all. Those have also become badly invasive.”

He spied my creeping jenny on a slope: “Another nasty invasive.”

He condemned to death my rose of Sharon shrubs (natural areas “have really been torn up by these guys”) and my innocuously named summer snowflake viburnum.

Worst was my row of nandinas — “heavenly bamboo” — along the foundation. “You definitely want to remove it,” he advised. Its cyanide-laced berries poison birds.

Condon:  This tactic is typical of the followers of Tallamy who want folks to perceive supposedly invasive plants as “bad” even though no evidence exists to support their accusations, especially in this instance.  Mr. Millbank and Mr. Bright, who obviously supplied this information, have misspoken here.  A study out of the University of North Carolina, Chapel Hill, published in 2022, explains that Cedar Waxwings are the only birds that might be poisoned, and that’s only going to happen if someone grows so many nandinas that these birds consume large numbers of fruits in a single feeding bout.  If you grow just one or even a few plants, you are not going to poison waxwings.

Conservation Sense and Nonsense:  Here in California, most berry-producing, non-native plants are considered “invasive” based on the assumption that birds eat the berries and spread the plants.  Nandina was briefly on the list of invasive plants in California until knowledgeable people informed the California Invasive Plant Council that birds don’t eat the toxic berries.  Nandina was removed from the invasive plant inventory long ago.

Bumblebee on Cotoneaster, Albany, CA. Cotoneaster is one of many berry-producing non-native plants on the list of invasive plants in California. Himalayan blackberries are another target for eradication in California. They are frequently sprayed with herbicide in public parks where children and other park visitors eat the blackberries.

I also have personal experience with nandina and cedar waxwings.  Flocks of waxwings visited my holly trees in San Francisco every year.  They did not touch my three nandina plants.

California buckeye (Aesculus californica) is an example of a native tree that is toxic.  Its flowers are toxic to honeybees and its big brown seeds for which it is named were used by Indigenous people to stun fish to make them easier to catch.  The bark, leaves, and fruits contain neurotoxic glycoside aesculin.  Every negative characteristic attributed to some non-native plant species is equally true of some native plant species.  No one mentions buckeye’s toxic characteristics because it’s a beautiful native tree.  Photo Sacramento Tree Foundation

Condon:   I’ve had a Rose of Sharon (Hibiscus syriacus) growing in my yard since I moved to my home in Virginia almost 40 years ago. In all this time, only one seedling from the plant I brought here has ever “volunteered” to become a second yard denizen.  During the past 37 years, pollinators have fed at the original plant and then also at its offspring. What I’ve found by experience in my yard is that few plants can successfully move into a space that’s already filled with other plants. (Proving what physics tells us–that no two physical objects can occupy the same space).  I’ve brought home numerous so-called invasive plants, only to have them disappear or simply stay put where I planted them. That’s because hundreds, if not thousands, of plants fill my yard. 

Conservation Sense and Nonsense:  Virginia is one of only four states in which rose of Sharon is considered invasive.  Condon’s experience with rose of Sharon in Virginia suggests that lists of “invasive plants” are either inaccurate or are serving another purpose (perhaps both).  The longer the list of “invasive plants” the more work is created for the “restoration” (AKA eradication) industry.

Rose of Sharon is not considered invasive in California. This is a reminder that the behavior of plants varies because of the wide range of climate and environmental conditions.  Nearly one third of the plants on California’s list of invasive plants are not considered invasive in California.  They are on the list because they are considered invasive in Hawaii, a state with a warmer, wetter climate than California.  In naming rose of Sharon as a dangerous invasive, a media resource with a national readership has made a generalization that red-lines more plants than necessary.  They become targets for eradication with herbicide and they deprive us of the biodiversity that is particularly important in a changing climate in which biodiversity ensures resiliency.

Millbank:  Bright did praise two “good” species I have that contribute to biodiversity: a sycamore and a catalpa as well as a “great” American elm and a “phenomenal” dogwood. (I couldn’t take much pride in them, though, because all four were here long before I arrived.) And Bright assured me I wasn’t a particularly egregious offender; my one-sixth acre lot in town is typical of the urban/suburban landscape.

●  ●  ●

Lawns, and those useless, ubiquitous cultivars of trees, shrubs and perennials sold by the major garden centers, are squelching the genetic variety nature needs to adapt to climate change.

Reese:  It’s actually the opposite. We need more plants in the mix. We need “the tumult of nature” to decide. We aren’t the jury, and we continue to interfere with our well-intended assumptions that we know best.

Lawns are full of wildlife when management is minimal. Mow. That’s all. Mow judiciously when “lawn weeds” are blooming. Watch birds feed on the many insects in the lawn including lepidopteran larvae. Realize that many moths pupate underground. Think of your lawn as haven for them and for the grubs birds relish as millions of acres across our country are being tilled for factory farms. Remember that the best habitat is mixed. Open areas bordered by wooded areas and most species love the borders. Our suburban landscapes are ideal if we just stop killing things.

This is a lawn that serves pollinators. Homestead Stencil Company

Millbank:  The resulting loss of native plants in our fragmented urban and suburban landscapes deprives both plants and wildlife of the contiguous habitats they need to breed and, over time, to migrate in response to climate change.

The deck is stacked against nature in this fight.

●  ●  ●

If possible, you should remove the nastiest of the invasive plants if you have them: burning bush, Japanese barberry, Asian bush honeysuckle, English ivy, callery (Bradford) pear and a few others.

But leave the rest of your plants alone, for now. Tallamy ultimately wants to cut lawn acreage in half, but “there is room for compromise,” he said. Think of your noninvasive plants and cultivars as “decorations.”

Janet Davis, who runs Hill House Farm & Nursery in Castleton, Va., has a similar message for the purists who make you feel bad about your blue hydrangea. “Don’t give me crap about something that’s not native but not invasive,” she said. “I’m never going to tell you you can’t have your grandmother’s peony.”

Thus absolved, I shed my guilt about my yard full of ecological empty calories. I kept my hydrangeas, azaleas and roses but pulled out the truly bad stuff. I dug up the nandinas and replaced them with native winterberry holly, red chokeberry and maple-leaf viburnum. I removed the rose of Sharon and substituted American hazelnut and witch hazel. I uprooted the invasive viburnum and planted a native arrowwood viburnum in its place.

I also took a small step in the painful task of killing my beloved lawn. I used landscape fabric to smother about 400 square feet of turf. In its place, I planted a smattering of canopy trees (two white and two northern red oaks), understory trees (ironwood, eastern redbud), shrubs (wild hydrangea, black haw viburnum) and various perennials and grasses (Virginia wild rye, blue-stemmed goldenrod, American alumroot, woodrush, spreading sedge).

My 38 plants cost $439 at Earth Sangha. But these natives, adapted to our soil and conditions, don’t require fertilizer, soil amendments or, eventually, much watering. Over time, I’ll save money on mulch and mowing.

Reese:  This one is so oft repeated and so very wrong. It depends on the plant, and it depends on the site. Plants in the wild require no input to succeed whether native or not because we have not messed up the soil and we have let the natural cycles of plant debris/decay improve the soil as it was meant to, creating a live, moist, interaction of microorganisms that work symbiotically to support the plant, which, btw has also been selected by nature for that site. It has absolutely nothing to do with origins. In fact, why would nonnative plants become “invasive” if they did not adapt as well or better than the native plants? I want to snort with laughter!

Millbank:  Right now, my seedlings look pretty sad. Where once there were healthy lawn and vibrant shrubs, there is now mud and scrawny sprigs poking from the ground every few feet. I put up chicken wire to keep the kids (and me) from trampling them. The carcasses of my invasive plants lie in a heap on the gravel.

Condon:  This statement supports my contention that ridding your yard (and, in the case of government, natural areas and parks) of “invasive” plants destroys habitat, leaving our wildlife high and dry.  Follow the advice of Doug Tallamy, via Dana Millbank (and many others) and you make the environment far less hospitable to our wildlife by removing plants that supplied habitat NOW when our critters need it to survive.

Conservation Sense and Nonsense:  This description of Millbank’s ravaged garden is consistent with my 25 years of observing native plant “restorations” on public land.  They all begin with destruction, usually accomplished with herbicides.  The first stage of these projects is often described as “scorched earth.”  Years later, there is rarely habitat comparable to what was destroyed.  Colored flags usually outnumber plants. 

This is what a native plant garden on Sunset Blvd in San Francisco looked like after two years of effort: more colored flags than plants. The sign claims it is “pollinator habitat.” Since when do pollinators eat flags?

Millbank:  But in a couple of seasons, if all goes well, my yard will be full of pollinators, birds and other visitors in need of an urban oasis. Years from now, those tender oak seedlings, now 6-inch twigs, will stretch as high as 100 feet, feeding and sheltering generations of wild animals struggling to survive climate change and habitat loss.

Conservation Sense and Nonsense:  Destroying harmless vegetation contributes to climate change by releasing carbon stored in the living vegetation and reducing the capacity to sequester more carbon.  Above-ground carbon storage is proportional to the biomass of the living vegetation.  Destroying large, mature plants and trees releases more greenhouse gases in the atmosphere than the young plants and trees can sequester.  Meanwhile, the climate continues to change and the native plants that Millbank prefers are less and less likely to be adapted to conditions.  Native plant ideology is a form of climate-change denial. 

A small forest of non-native trees was destroyed in a San Francisco park to create a native plant garden. Nine months later, this is what the project looked like: a tree graveyard.

Millbank:  I won’t be alive to see it. Yet even now, my infant oaks give me something the most stunning cherry blossom never could: a sense of hope.

Conservation Sense and Nonsense:  I feel bad for Dana Millbank.  He has been successfully guilt-tripped into believing he has damaged the environment.  He hasn’t, but destroying his harmless garden WILL damage the environment. 

We hope he will find his way back to a less gloomy outlook on nature, which will outlast us all in the end.  Altered perhaps, but always knowing best what it takes to survive.  The way back from the cliff he is standing on is through a study of evolutionary change through deep time to appreciate the dynamic resilience of nature, which may or may not include humans in the distant future.  Our message is “Embrace the change because change will enable survival.”

Suggested reading for those standing on the steep cliff created by nativism in the natural world:

California’s “Sustainable Pest Management Roadmap” is a 25-year poisonous pathway

California’s Department of Pesticide Regulation (DPR) has published a draft of a policy that would replace its Integrated Pest Management policy with a Sustainable Pest Management (SPM) policy that is different in name only.  SPM makes a commitment to continue using pesticides in California until 2050, and by implication, beyond.  It makes NO commitment to reduce pesticide use or reconsider the current targets of pesticide applications.  It claims that the health hazards and damage to the environment will be reduced by identifying “Priority Pesticides” for possible substitution or “eventual elimination.”  It doesn’t commit to identifying any specific number of dangerous pesticides nor does it provide specific criteria for selecting these dangerous products.  It claims that increased testing and development of new products will result in safer products and puts these judgments into the hands of “stakeholders” with “experiential and observational knowledge” rather than scientists with expertise in soil science, endocrinology, toxicology, epidemiology, biology, botany, horticulture, etc.  The “stakeholder” committee that wrote the SPM proposal for urban areas included the manufacturer of pesticides and other users and promoters of pesticides. 

That’s not an exhaustive list of the many faults of SPM and the dangers that lurk in it.  I hope you will read it yourself and consider writing your own public comment by the deadline on Monday, March 13, 2023, at 5 pm.  The document is available HERE.  It’s less than 100 pages long and it is a quick read because it is basically a collection of bullet-points.

This is how to comment:  “DPR is accepting public comments to inform the prioritization and implementation of the Roadmap’s recommendations through March 13, 2023 at 5 p.m. Comments can be shared in writing to alternatives@cdpr.ca.gov or by mail to the department at 1001 I Street, P.O. Box 4015, Sacramento, CA 95812-4015.” Please note that Department of Pesticide Regulations is not offering revisions, only “prioritization and implementation.” 

My public comment on California’s “Sustainable Pest Management Roadmap”

 A summary of my public comment is below.  A link to the entire comment is provided at the end of the summary:

Public Comment on
“Sustainable Pest Management Roadmap”
(AKA “Pathway to poisoning the environment for another 25 years”)

My public comment is focused on pesticide use in urban areas because of my personal experience and knowledge of pesticide use where I live.  These are the broad topics I will cover in detail with specific examples later in my comment:

  • Since glyphosate was classified as a probable carcinogen by the World Health Organization in 2015 and the manufacturer of glyphosate settled 100,000 product liability lawsuits by awarding $11 billion to those who were harmed by glyphosate, public land managers have been engaged in the process of substituting other, usually equally or more dangerous herbicides for glyphosate to deflect the public’s concerns.  The Sustainable Pest Management Roadmap (SPM) formalizes this process of substitution without addressing the fundamental problems caused by pesticides. 
  • SPM endorses the status quo that exists now.  Affixing the word “Accelerating” to SPM is an extreme case of double-speak that deliberately obscures, disguises, distorts, or reverses the meaning of words.  SPM ensures that toxic pesticides will be used in California for more than 25 years, to 2050, and likely beyond.  SPM therefore accelerates the damage to the environment that is occurring now.  Given that climate change will enable the movement of more pests into areas where they are now suppressed by weather, greater use of pesticides should be anticipated so long as the underlying issue is not addressed.
  • The underlying issue is that pests have been identified for eradication that in some cases cannot be eradicated and in other cases should not have been identified as pests either because they are innocuous or because of the valuable ecological functions they perform.  The key question that SPM does not address is whether pesticide use is truly necessary in the first place.  Unless we focus on whether a pesticide is actually necessary, all other issues are merely window dressing for perpetual pesticide use. 
  • SPM proposes to identify “Priority Pesticides” for possible substitution without any clear definition of “Priority Pesticides,” a process that is ripe for manipulation. Given the substitutions that are occurring now, we cannot assume that further substitutions would be less toxic. SPM puts the classification of “Priority Pesticides” into the hands of “stakeholders” without clearly identifying who stakeholders are.  SPM says “stakeholders” were involved in the development of the proposed policy.  Those stakeholders included only users and promoters of pesticide use.  There was no representation on the Urban Sub-Group of organizations such as Californians for Pesticide Reform, California Environmental Health Initiative, Beyond Pesticides, Center for Environmental Health, Environmental Working Group, etc.  Nor was there any visible expertise in the fields of science that are capable of analyzing and evaluating the impact of pesticides, such as soil science, endocrinology, toxicology, entomology, botany, biology, or horticulture.  SPM ensures that this exclusion will continue during the implementation phase by suggesting that “experiential and observational” knowledge should be represented on an equal footing with undefined “science.”  The word “science” is being used and abused by advocates for pesticide use who dangle it as a magic talisman, conferring fraudulent credibility. 

My entire public comment is available here:

The Oxalis Obsession

As a long-time reader of Jake Sigg’s Nature News, I am very familiar with his passionate crusade against Oxalis pes-caprae.  When oxalis appears in the landscape in January, Jake gears up his campaign again. This year the Westside Observer published an article by Jake about oxalis that reaches a new level of urgency and asks land managers to increase their use of herbicides to kill the plant.

In the past, Jake has advised careful and relentless hand-pulling of oxalis with its bulb intact.  Now he acknowledges that hand-pulling is useless to eradicate oxalis.  Although herbicides have been used on oxalis in San Francisco’s parks for 25 years, Jake now wants MORE herbicides to be used. Over 20% of all herbicide spraying by the Natural Resources Division (NRD) of the Recreation and Park Department was applied to kill oxalis in “natural areas” in 2022. NRD sprayed oxalis 35 times in 2021 and 38 times in 2022.

Spraying Garlon on Twin Peaks in San Francisco, February 2011

From January to March, virtually all the herbicides sprayed by NRD in the so-called “natural areas” were sprayed on oxalis.  If it were possible to eradicate oxalis with herbicide, why is there more oxalis now than there was 25 years ago, when NRD (then known as the Natural Areas Program) started spraying herbicides in the “natural areas?”  A lot of herbicide has flowed under the bridge in the past 25 years, but oxalis thrives. What is the point of pouring more herbicide under the bridge of sighs?  We’re pouring more fuel on the fire with nothing to show for it. 

One of many pesticide application notices on oxalis in Glen Canyon Park in February 2023.

The University of California Integrated Pest Management Program explains why it’s not possible to eradicate Oxalis pes-caprae with herbicides: “Several postemergent herbicides including triclopyr and fluroxypyr (selective for broadleaf plants) and glyphosate and glufosinate (nonselective) effectively kill the top growth of this weed but are harmful to most ornamentals, so be careful these herbicides don’t drift onto desirable plants. These herbicides don’t kill the bulbs, and regrowth from bulbs should be expected.” In other words, you can kill the above-ground top growth and other non-target plants in the vicinity, but you won’t kill the oxalis. 

Chemical Warfare?

On one hand, Jake urges public land managers to escalate chemical warfare against oxalis.  On the other hand, he accuses oxalis of “chemical warfare” (AKA allelopathy), secreting chemicals that kill other plants. This accusation is pure speculation on Jake’s part.  He offers as “evidence” of his speculation that after oxalis dies back in April “we’re left with bare ground for the rest of summer and autumn.”  He ignores the obvious fact that annual spraying of gallons of herbicide on oxalis in the “natural areas” could be causing the bare ground. It has apparently not occurred to him that many herbicides are non-selective, killing everything they touch, not just targeted plants. And those herbicides that claim to be selective are very mobile in the soil, capable of killing adjacent plants through their roots.  If you don’t want to see bare ground, don’t spray herbicides!

Jake asks for more research on how oxalis interacts with other plants in his article published by Westside Observer. He is apparently unaware of the research that has been done by scientists at University of Montana to address the question of how competitive oxalis is in plant communities that include native plants:  “Oxalis is a poor competitor. This is consistent with the preferential distribution of Oxalis in disturbed areas such as ruderal habitats, and might explain its low influence on the cover of native species in invaded sites.

The study explains why oxalis does not suppress the growth of other plants, including natives.  Oxalis makes more phosphorous available in the soil, which essentially acts as a fertilizer for other plants“These results are consistent with our field data and suggest that Oxalis may improve P availability in the field.”

This study was published in 2007.  It found that Oxalis pes-caprae does not suppress the growth of other plants and, in fact, increases nutrients in the soil.  Jake apparently doesn’t know about this study and related studies that found that pollinators are as interested in O. pes-caprae as they are in native plants.

Jake’s accusation that oxalis is waging “chemical warfare” against native plants does not come out of nowhere.  The same accusation was used against eucalyptus trees for decades until a definitive empirical study proved that eucalyptus is not allelopathic.  The California Invasive Plant Council removed that accusation from its evaluation of Blue Gum eucalyptus in 2015 (along with the accusation that eucalyptus kills birds).  As the readers of Jake’s Nature News know, his hatred of eucalyptus is second only to his hatred of oxalis.  There was never evidence that eucalyptus is allelopathic and there is no evidence that oxalis is allelopathic.

Does biodiversity justify poisoning nature?

Jake justifies his crusade against oxalis based on his belief that its existence threatens biodiversity.  Since there is no evidence that oxalis kills other plants, there is no reason to believe its existence threatens biodiversity.  

Jake also asks us to include only native plants in the measure of biodiversity, but he is alone in that belief.  Scientific measurements of biodiversity include all species of plants and animals, whether considered native or non-native.  The Recreation and Open Space Element of San Francisco’s General Plan explicitly acknowledges that both native and non-native plants contribute to biodiversity:  “Parks and open spaces in San Francisco include both native and non-native species, both of which can contribute to local biodiversity.” (Policy 4.1, Recreation and Open Space of San Francisco General Plan)

Jake ups the ante against oxalis by claiming that wildlife requires solely native plants, a fundamental tenet in native plant ideology.  Again, this claim is unsupported by evidence.  As Professor Art Shapiro (UC Davis) says in his Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions, “Most California natives in cultivation are of no more butterfly interest than nonnatives, and most of the best butterfly flowers in our area are exotic.”

coyote hunting in oxalis field. Copyright Janet Kessler

On one hand, Jake claims that oxalis deprives birds and other foragers of food.  On the other hand, Jake acknowledges that oxalis is foraged by gophers and scrub jays (based on one observation).  Jake wants it both ways because that serves his purpose. 

If native plants were any benefit to wildlife, that benefit is quashed by the widespread use of herbicides being used in the “natural areas.”  For example, Himalayan blackberries are an important source of food for birds and other wildlife in San Francisco’s parks and are also eaten by children visiting the parks.  The blackberries are routinely sprayed with herbicides in the so-called “natural areas.”  Wildlife is exposed to the herbicides and they are also deprived of important sources of food.

A recent survey of 24,000 gardens in the UK found that pesticide use had a significant effect on bird life. The study found that gardens that used pesticides had fewer species of birds than similar gardens that did not use pesticides:

“Pesticide spraying impacted the positive effect [surrounding habitat quality] had on bird richness. Specifically, ‘species richness [number of species] increases with the surrounding quality, both for gardens that do not use pesticides and for gardens that applied pesticides, but this effect is significantly less strong when pesticides are applied’ the study indicates. Scientists zeroed in on three active ingredients: the weed killer glyphosate, the neonicotinoid insecticide acetamiprid, and the synthetic pyrethroid deltamethrin as resulting in the most damaging pesticide impacts to bird species’ richness.” Note that the study’s definition of “surrounding habitat quality” made no distinction between native and non-native plants.  The British are not strong supporters of native plant ideology. 

Nativists keep using huge quantities of herbicide to kill vegetation they don’t like, while also claiming that their eradication projects benefit birds. This is a fundamental contradiction. Their eradication projects are harmful to birds and other creatures that live in our parks and open spaces.

Jake’s Lament

In his article, Jake laments that people are accepting changes in the landscape because they don’t remember what the landscape looked like 100 years ago.  His “baseline view” of what landscapes should look like is much further in the past than most people’s memories of the landscape. 

The climate has changed significantly in the past 100 years.  When the climate changes vegetation changes.  We should welcome the changes because they are required for the survival of any landscape.  When the climate changes, plants and animals must move, adapt, or die.  The changing landscape is an indication that plants are adapting to changing conditions. 

We cannot stop evolution, nor should we try.  Herbicides are a futile attempt to stop evolution.  Herbicides cannot stop evolution, because plants evolve a resistance to them.  After 25 years of constant herbicide use in San Francisco’s parks and open spaces, we should assume that they are less effective every year. 

While San Francisco’s Recreation and Park Department has significantly reduced its use of herbicides since 2010, the Natural Resources Division that is responsible for the “natural areas” has not. Natural Resources Division is now using more herbicides than the rest of the parks. Source: San Francisco IPM Program, Department of Environment

Wild by Design: A history of ecological restoration in the U.S.

“This is a superb book. Laura Martin’s research takes us where no restoration literature has gone before, asking, ‘Who gets to decide where and how wildlife management occurs?’ Martin tackles this question with unmatched clarity and insight, illuminating the crucial discussions we must have to secure a future with thriving natural species and spaces.”—Peter Kareiva, President and CEO, Aquarium of the Pacific

The author of Wild by Design, Laura J. Martin, is a professor of environmental history at Williams College.(1) She has written a comprehensive history of ecological restoration in the US that is consistent with my own observations of the restoration industry in the past 25 years.  It’s a story of the gradual transition from a conservation ethic to a preservation ethic and finally to the restoration ethic that we see today.  The story is punctuated by milestone federal laws and actions that facilitated the transition.  Environmental non-profits and academic ecologists used those laws to professionalize and monetize the restoration industry that exists today. 

By the end of the 19th Century, the public began to react to the environmental degradation caused by unregulated resource extraction.  In 1902, a survey of naturalists around the country determined there were 1,143 bison left in the country; virtually all were in captivity.   The American Bison Society was founded in 1905 in reaction to the disappearance of bison in America.  Their activism led to the creation of federal game reserves on former Indian reservations where captive bison were introduced.  The game reserves were the model for the National Wildlife Refuge system that was greatly expanded by President Teddy Roosevelt.

A photograph from 1892 of a pile of American bison skulls in Detroit, Michigan waiting to be ground for fertilizer or charcoal. (Photo Wikimedia Commons)

The creation of the Wild Flower Preservation Society (WFPS) in 1901 was modeled on the successful campaign of the Audubon Society to save birds killed to serve as ornaments on fancy hats.  It was as much a campaign to shame women into abandoning the fashion fad as it was an effort to legally ban the practice.  Likewise, the Wildflower Preservation Society applied social pressure.  They were critical of organized excursions to visit wildflowers because they picked and trampled the wildflowers.  WFPS said that “Weddings are a new menace to our native plants” because of their use of wild flowers. Their criticism was initially aimed at their own community, but “it moved toward policing the behavior of so-called new immigrants to the United States—especially children.”  The moralistic scolding by these early native plant advocates was a preview of the finger-wagging now aimed at those who choose to plant a diverse garden. 

These advocacy organizations are precursors to the many environmental non-governmental organizations that are influential in pressuring government to invest in ecological restorations today.

Conservation and Preservation

The goals of conservation and preservation are similar, but some differences were observable in the past 200 years.  Both ethics are committed to protecting the environment, but conservation allows the sustainable use of natural resources while preservation protects nature from use.  The presidencies of both Teddy and Franklin Roosevelt were committed to conservation. 

Teddy Roosevelt created the US Forest Service based on the premise that government can and should regulate public lands to manage natural resources.  Franklin Roosevelt’s conservation programs were based on the same principle, but were motivated by the economic emergency of the depression as well as the environmental disaster of the Dust Bowl in the Midwest.  The Civilian Conservation Corp (CCC) was created to provide jobs as well as to plant a “shelter belt” of trees across the Midwest of the country as a windbreak to stop dust storms (and many other projects).  Ecologists were critical of CCC projects because they expanded recreational opportunities and put “a stamp of man’s interference on every natural area they invade.” They preferred to exclude humans and their activities from nature. This is another early indicator of the conflicts between preservation and conservation that persist to the present day.

Sharp Park, Pacifica, CA. Photo by Erica Reder, SF Public Press

Government investment in ecological research

Ecological research in the United States was fundamentally altered after World War II, which ended with the beginning of the atomic era.  Atomic bombs were dropped on Japan to end the war without much thought given to the consequences.  After WWII, the federal government made big investments in science, creating the Atomic Energy Commission and the National Science Foundation, which funded ecological research to study the impact of radiation on the environment and those who live in it.  Conservation Sense and Nonsense published an article about those studies and the impact they had on ecological research. 

These studies legitimatized destruction of ecosystems to study effects of the destruction and the concept was expanded from radiation to pesticides in the 1960s.  They also provided funding to the academic profession of ecology that was small and is now enormous.  The dependence of ecological studies on government funding remains to this day and government funding of ecological projects has created the restoration industry that now extends far beyond academia.  Destruction of existing habitat is still considered the prerequisite to restoring a historical landscape.  Often, destruction is the first and only stage of the project because of the persistent fantasy that the native landscape will regenerate without further help. 

In the late 1960s Daniel Simberloff tented and fumigated 6 mangrove islands off the eastern short of Florida with methyl bromide to kill all life on the islands.  The objective of the project was to study how long it would take to repopulate the islands with insects.

From Conservation to Restoration

The post-war economic boom of the 50s and 60s greatly increased the impact of human activities on the environment.  The federal government built a vast highway system that fragmented and disrupted ecosystems.  We built huge dams, and channeled riparian ecosystems.  Open space was rapidly covered by housing and industrial development.  Wetlands were drained and filled with rubble to create more land.

People who cared about the environment began to react to the loss of nature and wildlife that lives in nature.  Although Aldo Leopold is idolized by the native plant movement, his concern about the degradation of nature was primarily for wildlife.  His interest in vegetation was as habitat for wildlife.  He was opposed to government programs devoted to killing animals perceived as predators of game animals because he believed that wildlife is best served by expanding their habitat.  In fact, he was opposed to the expansion of government’s role in conservation because “he believed restoration would be most efficient and effective if pursued by private citizens.” He did not prefer native plants because “Farmers had the opportunity to conserve plants such as ragweed and foxtail (an introduced grass), ones ‘on which game, fur, and feather depend for food.’”  In other words, in the 1940s one of the icons of the native plant movement knew that wildlife is not dependent upon native plants for food.  One wonders if native plant advocates have actually read Leopold’s treatise, A Sand County Almanac. 

Aldo Leopold’s son, Starker Leopold, had as much impact on conservation in the United States as his father.  In 1963, he published the Leopold Report that changed the direction of conservation in the National Park Service.  The Leopold Report recommended a goal for national parks of maintaining historical conditions as closely as possible to those of “primitive America.”  When the Leopold Report was adopted as official policy by the National Park Service in 1967, it committed NPS to restoring park lands to pre-settlement conditions. NPS officially changed this policy in 2021, but we don’t see any change locally in their projects because NPS is decentralized and local parks are autonomous.

Restoration Goals

Professor Martin says that “historical fidelity did not become a widespread restoration goal among ecologists and environmental organizations until the 1980s.”  The arrival of Columbus in the new World in 1492 was arbitrarily selected as the date after which all new plant species were “deemed nonnative, unwanted reminders of human (colonist) presence and activity.”  On the West Coast, 1769 is the equally arbitrary date to confer non-native status because it is the date of the first Spanish expedition to California. 

Many now question the goal of replicating historical landscapes.  After 40 years of effort, there is a growing recognition that it is not a realistic goal, especially in a rapidly changing climate.  The Society for Ecological Restoration has changed its definition of ecological restoration from “the goal of intentionally altering a site to establish a defined, indigenous, historic ecosystem” in 1990 to “the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed” in 2002.  Try telling that to the restorationists on the ground who are still trying to eradicate naturalized non-native plants that have been here for nearly 200 years.  Non-native annual grassland in California is a case in point. It has been repeatedly burned, mowed, plowed, and poisoned for 25 years without any visible progress toward native perennial grassland.   

Blaming non-native species

Around the same time that historical fidelity was identified as the goal of “restorations,” land managers and ecologists decided that the existence of non-native species is the main threat to native species.  I suppose the “logic” was that the main difference between historical landscapes and present landscapes is the existence of non-native species.  Concern about non-native species spread among federal agencies such as the National Park Service and The Nature Conservancy (TNC) began aggressive campaigns to kill non-natives, “which were newly framed as the main threat to wild species…nativity would become a precondition to wildness—of plants and animals both.”   TNC’s methods have become increasingly deadly and destructive: using fire and herbicides to kill plants, poisoning honeybees, aerial hunting of sheep, pigs, and goats.  As a former donor to TNC, their methods finally became intolerable to me.

Professor Martin believes that the identification of non-native species as the scapegoat was not based on experimental evidence, but merely a description of the strategies used by public land managers, as well as The Nature Conservancy.  Non-native species were a convenient scapegoat because they were easily identified and were an easy substitute for identifying and remediating the underlying conditions causing so-called “invasions.”  “Although the role of invasive species in native species extinction has since been challenged by some ecologists, the influence of this fear on species management has been enormous…The US federal budget for invasive species management increased by $400 million between 2002 and 2005, for example.”   

Endangered Species Act

The Endangered Species Act (ESA) was passed in 1973, along with companion laws such as the National Environmental Protection Act and others.  These federal laws created more funding opportunities for ecological projects as well as the legal justification for ecological restoration projects.

Federal laws permit the reintroduction of legally protected plant and animal species to places where they no longer exist.  The ESA confers the same protections for reintroduced species as it does for naturally occurring species.  Such reintroductions have become a tool for the restoration industry.  I have seen that strategy used in the San Francisco Bay Area.  If we had not been successful in preventing the reintroduction of a legally protected turtle, it would have justified the destruction of the non-native forest in my neighborhood park because the turtle requires unshaded nesting habitat within 500 feet of the water source in the park. The park remains largely forested because that is one of the few battles we have won in 25 years. Reintroduced, legally protected species are the Trojan horses of ecological restorations.

Compensatory mitigation is an equally powerful tool for the restoration industry.  Federal law requires an Environmental Impact Statement (EIS) for projects that will have a significant impact on the environment, such as big developments like building Disney World in Florida.  Disney World was built on an enormous wetland that was lost by the development of the park.  The EIS for the project agreed that the impact would be great, but it “mitigated” the impact by requiring Disney to fund the creation of a new wetland in a distant location.   

The funding generated to create fake wetlands built a new industry of commercial companies to design and build them.  Academic restoration ecologists questioned the functional equivalency between created and natural wetlands:  “’however accurate [the Comprehensive Everglades Restoration Plan] is the restored community can never be authentic.’”  The tension between commercial and academic restorationists continues today.

The Society for Ecological Restoration published findings that mitigation wetlands were not functionally equivalent to the wetlands they were meant to replace.  In Florida only half of the promised mitigation projects were actually built. Those that were built were colonized by “undesirable plant species” such as cattail and melaleuca in 32 of 40 projects.    

Projects that earn carbon credits are creating the same opportunities to generate funding for restoration projects in distant locations.  The Nature Conservancy was successful in defining carbon offsets as an international market when the Kyoto Protocols were signed in 1997.  They understood that a reforestation project would be cheaper in Costa Rica (for example) than a comparable energy efficiency project in the US.  Such distant projects don’t benefit those in the US who now have a power plant in their backyard that is being offset by a forest in Costa Rica. 

It’s a game for those who know how to play.  I have witnessed local examples in the Bay Area.  An oil spill in the bay generated millions of dollars of compensatory damages to fund unrelated “restoration” projects.  How does planting eel grass compensate for hundreds of birds killed by the oil spill?  When the San Francisco airport expanded runways, the airport had to pay compensatory mitigation that funded the restoration of native plants at India Basin in San Francisco that hardly compensates for the increased air traffic enabled by the new runway.   

Conclusion

Professor Martin is surprisingly frank about the future of ecological restoration in America:

“Whatever paths restorationists choose, restorations must happen in tandem with other changes in human behavior.  If we don’t reduce the ongoing harms of racism, fossil fuel burning, overconsumption by the wealthy, and toxic industrial chemicals, restoration will offer no more than a temporary repair, a way to move a problem to some other place or time.”

I would go one step further in my assessment of the restoration industry.  I would say that the methods used by restorationists are directly contributing to environmental degradation. 

Professor Martin asks the right questions in her concluding chapter:  “Who benefits from restoration?  Who is harmed?”  Those who earn their living in the restoration industry are the primary beneficiaries. According to a 2015 study entitled “Estimating the Size and Impact of the Ecological Restoration Economy,” environmental regulation has created a $25 billion-per-year restoration industry that directly employs more people than coal mining, logging or steel production.  Given recent investments in restoration projects of billions of dollars by California and federal infrastructure funding, this figure is undoubtedly an underestimate. 

Who is harmed?  Wildlife and humans are harmed by the destruction of useful habitat with herbicides.  Harmless animals and plants are killed because they have been arbitrarily classified as “invasive.” And all Americans are harmed by the waste of public funds that could be used to benefit society and/or the environment. 


(1) Laura J. Martin, Wild by Design:  The rise of ecological restoration, Harvard University Press, 2022.  All quotes are from this book.

Part III: Appealing to the City of Albany to save its eucalyptus forest

I am publishing my letter to the Albany City Council about the City’s plans to destroy most of the eucalyptus forest on Albany Hill.  I am publishing it in three segments because it is long.  The first segment explained why it is not necessary to destroy the forest.  The second segment explained the consequences of destroying the forest.  The third and final segment explains why it is unlikely that the forest can be replaced by native trees.

Now you have my version of the full story. If this is a place or an issue you care about, please consider writing a letter of your own to the City Council of the City of Albany.

Conservation Sense and Nonsense

Albany Hill. Source: Google Earth


December 5, 2022

Albany City Council
1000 San Pablo Ave.
Albany, CA 94706

Dear Albany City Council:

SEE Part I and Part II of Appealing to the City of Albany to save its eucalyptus forest.  Part III is the concluding segment:

The uncertain fate of monarchs on Albany Hill is a suitable introduction to my final issue.  The proposed plans for Albany Hill claim the destroyed eucalyptus forest will be replaced by new trees. I will explain why it is unlikely that the eucalyptus forest can be replaced by another forest. Plans for a newly planted forest are described in various ways, some of which seem contradictory:

  • “[Margot] Cunningham’s [Albany’s Natural Areas Coordinator] team is pursuing grants to cut down most of the blue gums and plant the city’s side of the hill with a mix of native species and more drought tolerant trees for monarchs to roost.” (1)
  • “WHEREAS, the City is investigating consultants to design a plan to remove eucalyptus in a way that retains and restores more fire-resilient native plant communities and minimizes soil disturbance and soil erosion.” (2)
  • “More droughty Eucalyptus species can be planted to preserve the butterfly habitat.” (3)
  • “This plan will include but is not limited to: plantings of other tall trees in areas of the hill where monarchs have traditionally clustered; survey of the existing native understory which will be allowed to grow after eucalyptus removal; and analysis and design of additional plants of Albany Hill-sourced native plants.” (4)

Somehow, this diverse, drought-tolerant, fire-resilient, tall, native (with droughty eucalyptus species?) forest is expected to survive without irrigation:  “If drought-tolerant tree species are planted as seedlings, in the fall with sufficient planting site preparation and adequate rain fall, minimal if any irrigation will be required.” (5)  When predicting the fate of the existing eucalyptus forest, the plans assume that the drought will continue.  When predicting the fate of a replacement forest, the plans assume that the drought will end. 

Most public land managers irrigate newly planted trees (whether native or non-native) for at least 3 years.  Established trees rarely require irrigation to survive because they have extensive root systems that have better access to moisture in the soil than newly planted trees without extensive root systems.  Tree species that are drought-tolerant when mature trees, require irrigation as they grow their root systems.  Replacing healthy trees that don’t require irrigation with new trees that require irrigation seems an unwise choice in the middle of an extreme drought. 

The City of Albany should have learned that lesson when they built Peggy Thomsen Pierce Street Park at the western foot of Albany Hill.  Only native trees were planted in that park.  They weren’t irrigated.  Five years after the park opened in 2017, most of the trees are dead (see below):

Peggy Thomsen Pierce Street Park, November 2022.  Conservation Sense and Nonsense

The City of Albany’s list of approved street trees is a valuable source of information about what tree species are capable of growing in Albany.  A tree species that cannot survive conditions for street trees is also unlikely to survive on the ridgeline of Albany Hill, where wind conditions are extreme and there is little moisture.  There are about 65 tree species approved for planting as street trees in Albany.  Five are native to California, but only three are native to the Bay Area.  Native big leaf maples are said to be “in decline.”  Buckeyes aren’t suitable street trees, but may be suitable for open space.  None of the listed native trees are suitable monarch habitat for a variety of reasons:  canopy too dense to provide sufficient sunshine; deciduous therefore bare in winter; short stature, etc. 

Historically, areas on Albany Hill that are now forested with eucalyptus were treeless because native trees are not adapted to the challenging climate conditions.  If the eucalyptus forest on Albany Hill is destroyed, Albany Hill is likely to be treeless again.  That is the horticultural reality of Albany Hill. 

In conclusion:

  • It is not necessary to destroy the eucalyptus forest on Albany Hill because it is not dead.
  • Destroying the eucalyptus forest on Albany Hill will increase fire hazards and safety hazards.
  • Destroying the eucalyptus forest will destroy habitat of monarch butterflies.
  • Plans to replace the eucalyptus forest with native trees are unrealistic.

Please consider reinstating the 2012 Albany Hill Creekside Master Plan.  It is still a good plan that will not do unnecessary damage to Albany Hill and its human and animal visitors.

cc: Albany Fire Chief
Albany Natural Areas Coordinator
Albany Urban Forester
Creekside Science


Update:  Shortly after I sent my letter to officials of the City of Albany about their plans to destroy most eucalyptus on Albany Hill, they revised their plans because of two updated reports that were done in November and December 2022.  Basically, they no longer plan to destroy most eucalyptus on Albany Hill for two main reasons:

  • Eucalyptus trees are the overwintering habitat of monarch butterflies. They cannot be replaced by native trees of short stature without the open canopy that filters sunlight but also provides a windbreak the monarchs need.
  • Epicormic sprouts on the eucalyptus trees indicate they are recovering from drought and are expected to survive and eventually replace their canopies.

These are the sources of information that corroborate my brief summary of the main reasons Albany is no longer planning to destroy most eucalyptus trees on Albany Hill:

They still intend to remove dead trees to reduce fuel loads, to which I have no objection.  Some dead eucalyptus may be replaced with more drought tolerant species of eucalyptus from Western Australia. 

To be clear, I don’t think my letter about their original plans for Albany Hill were influential in their revising their plans.  My letter is consistent with the advice they received from an ecologist with expertise in monarch butterflies and a consultant in fuels management.  Credit belongs to the preference of monarchs for eucalyptus and to eucalyptus for being indestructible.

April 2023


  1. Bay Nature:  https://baynature.org/2022/10/20/the-nearly-unkillable-eucalyptus-meets-its-match/
  2. Resolution No. 2021-105.  A resolution of the Albany City Council, authorizing the appropriation of funds to the Albany Hill Eucalyptus Project in the amount of $100,000
  3. https://www.albanyca.org/home/showpublisheddocument/52453/638028259461770000
  4. Staff Report to City Council regarding Albany Hill Eucalyptus Project, May 2, 2022
  5. https://www.albanyca.org/home/showpublisheddocument/52453/638028259461770000

Money and Fire: 2022 Conference of California Native Plant Society

The California Native Plant Society (CNPS) held a conference in October for the first time since 2018.  There were two main themes of the conference:

Money:  The State of California is making a huge investment in the environment with many interrelated goals:

  • “30 X 30” is shorthand for the goal of protecting 30% of California’s land and coastal waters by 2030.
  • Developing “nature-based solutions” to address the threats of climate change.
  • Vegetation and forest management to reduce wildfire hazards.
  • Protecting and enhancing California’s biodiversity.

Fire:  The frequency and intensity of wildfire is of concern to all Californians, but the California Native Society has a particular interest in fire because it is viewed as a tool to enhance native plant abundance and control the spread of non-native plants that outcompete native plants.

Money

If attendance were the sole measure of success, the conference was a resounding success.  The conference was sold out with record-breaking attendance of 1,200 people.  That’s a 50% increase in attendance since 2018, when 800 people attended.  People came to learn about the many opportunities for public funding of their “restoration” projects and they were not disappointed.

Jennifer Norris, Deputy Secretary for Biodiversity and Habitat for the California Natural Resources Agency (CNRA) was one of the keynote speakers.  She and many other staff of CNRA made presentations at the conference to inform the community of native plant advocates about the many new opportunities to obtain grants for their projects.  This slide (below) shown at the conference, itemized by state agencies the $1.631 Billion budget for just the 30 X 30 portion of the CNRA’s environmental grant programs.  It does not include Cal-Fire funding for forestry projects to reduce wildfire hazards and address climate change.  Nor does it include $10 million of new funding for Weed Management Areas, which funds projects that attempt to eradicate non-native plants and $10 million of new funding for the state council for invasive species. State funding is also supplemented by new federal funding in support of a national goal of achieving 30 X 30. 

But money isn’t the only element of this state program that native plant advocates are excited about.  They have also been gifted a three-year moratorium on requirements for Environmental Impact Reports for their projects.  There will therefore be no requirements for a public process to review plans and comment on them. 

An anxious applicant for state grant funding asked a speaker representing the Wildlife Conservation Board about a rumor that projects using herbicides would not be funded.  The speaker’s reassuring answer was, “We are not rejecting projects using herbicides.” Applicants are being asked to complete a questionnaire about herbicides they plan to use, but the speaker was quick to add, “We have not rejected any [such applications] so far.”  She assured the audience that “You are all careful” in your use of herbicides.

Huge buckets of money are being distributed with no restrictions on the use of herbicides and no vetting process such as an environmental impact review with opportunities for the public to comment.  It seems inevitable that some of the projects will unintentionally do more harm than good, and the public will have nothing to say about which projects are funded. 

Fire

Alexii Sigona was the first keynote speaker for the conference.  He is a member of the Amah Mutsun-Ohlone Tribal Band (not a federally recognized tribe) and a Ph.D. candidate at UC Berkeley in the Department of Environmental Science.  He explained that there are 600 recognized members of the Amah Mutsun Band in a wide region around Pescadero, Hollister, and San Juan Bautista.  They collaborate with organizations such as CNPS because they don’t have the resources to manage their ancestral tribal lands.  He described some of the projects they engage in:

  • Landscape scale removal of “invasive” plants.
  • Plug planting of 120,000 native grass plants.
  • Creating “native hedgerows” for food sources.
  • Removal of native Douglas Firs “encroaching” on grassland.  They have removed 5,000 native Douglas fir trees.  He acknowledged that this project caused some concern about erosion and aesthetics.  Removal of native Douglas fir was mentioned by several other speakers during the conference.  It is an example of the preference of native plant advocates for grassland because it is the pre-settlement vegetation.  Native coyote brush is another target of eradication projects that attempt to prevent natural succession of grassland to other vegetation types. 

There is great interest among native plant advocates in the land management practices of Native Americans because controlled burns were Native Americans’ most important tool to maintain grassland species needed for food and for their prey.  Controlled burns are important to native plant advocates because they believe they are beneficial to native plants and help to control non-native plants.  Prescribed burns are also currently popular with many public land managers and they are the current fad among many fire scientists. 

Two presentations at the conference suggest that prescribed burns are not compatible with the preservation of native chaparral, nor are they capable of converting non-native grassland to native grassland.

This (above) is the concluding slide of Jon E. Keeley’s presentation.  Dr. Keeley is a respected fire scientist with US Geological Service with expertise in chaparral species.  He explained that 60% of native chaparral species (notably manzanita and ceanothus) are obligate seeders that do not resprout after fire and therefore depend on the existence of their dormant seed bank for regeneration.  In recent decades the fire interval in chaparral has decreased due to climate change and associated drought.  In many places, the fire interval has become too short to establish the seed bank needed for regeneration.  In those places Dr. Keeley has observed vegetation type conversion to non-native annual grasses. 

Dr. Keeley Is concerned that vegetation type conversion from forests in some cases and shrublands in others to non-native annual grassland may be the result of shortening fire intervals further “because of the upsurge in state and federal programs to utilize prescription burning to reduce fire hazard.” (1) This concern extends to some conifer species that do not resprout.  Some are serotinous conifers whose cones are sealed shut and do not release their seeds in the absence of fire. 

This is a familiar theme for much of Dr. Keeley’s research.  He asks that land managers balance the conflicting goals of resource management and fire hazard reduction. 

This (above) is the concluding slide (sorry for the poor quality of my photo) of a presentation about a 20-year effort at the Santa Rosa Plateau Ecological Reserve to convert non-native annual grassland to native grassland, using annual (sometimes bi-annual) prescribed burns.  Many different methods were used, varying timing, intensity, etc.  The abstract for this presentation reports failure of the 20-year effort:  “Non-native grass cover significantly decreased after prescribed fire but recovered to pre-fire cover or higher one year after fire.  Native grass cover decreased after prescribed fire then recovered to pre-burn levels within five years, but never increased over time.  The response of native grass to fire (wild and prescribed) was different across time and within management units, but overall native grass declined.” (1)

The audience was audibly unhappy with this presentation.  One person asked if the speaker was aware of other places where non-native grass was successfully converted to native grass.  The speaker chuckled and emphatically said, “NO.  I am not aware of any place where native grasses were successfully reintroduced.” 

Another questioner prefaced her question with the admission that “I’m new here and all this is new to me.”  Then she suggested that Native Americans are having some success using prescribed fire and that they should be consulted.  The speaker graciously replied that she planned to do so. 

Keep in mind that Native Americans weren’t historically using prescribed fire to convert annual grasses to native grasses.  Their burns were intended to maintain native grassland in the absence of competing non-native annual grassland.  Their objectives were different and they were operating in a very different climate and environment. 

Estimates of the pre-settlement population of Native Americans in California range from 138,000 to 750,000.  The population of Native Americans is estimated to have been reduced to as few as 25,000 after the arrival of Europeans due to disease and violence.  There are now over 39 million Californians and only 630,000 of them were Native Americans in the 2020 census.  Land management practices that are suitable for a population of less than 1 million seasonally migrating Californians are not necessarily suitable for a population of over 39 million sedentary Californians.   

The futility of trying to eradicate non-native plants

The Invasive Spartina Project (ISP) is another 20-year eradication project that is doomed to failure.  The presentation about the ISP was bravely made by Dr. Debra Ayres, one of the creators of the ISP in 1998.  With intensive effort and hundreds of gallons of herbicide (imazapyr), non-native spartina marsh grass has been greatly reduced in the San Francisco Bay, but the hybrid of non-native S. alterniflora and native S. foliosa persists.  Dr. Ayres explained why:

The spartina hybrid is reproductively stronger in every way than either of its parent species.  Dr. Ayres predicts that the hybrid will eventually replace both of its parent species:

If the goal of this project was to eradicate non-native spartina, hybrid spartina will accomplish that goal. You might think that this prediction would end the futile attempt to eradicate the hybrid, but you would be wrong.  There is no intention of abandoning this 20-year project.  More funding is assured by the California Coastal Conservancy and the project continues to provide well-paid jobs. 

Dr. Ayres ended her presentation with this enigmatic statement:  Evolution doesn’t stop just because we think it has to.”  She seems to acknowledge that humans cannot stop evolution, yet she seems to recommend that we continue to try doing so.  If those positions seem contradictory, that’s because they are.  The bottom line is that as long as public funding continues to be available, this project will continue.

A central theme of the nativist agenda is the futile desire to prevent hybridization because it has the potential to replace a species considered “native.”  They fail to understand that hybridization is an important evolutionary tool that helps plant and animal species adapt to changes in environmental conditions by favoring traits that are better adapted to new conditions.  Humans cannot stop evolution, nor should we try.

San Francisco

I have a special interest in San Francisco because I lived there for nearly 30 years.  The native plant movement is very strong in San Francisco and there were several presentations about the success of the movement at the conference.

Sunset Blvd being built on barren sand in 1931

One of the projects is trying to turn Sunset Blvd on the western side of San Francisco into a native plant garden.  I lived in that district and am therefore familiar with Sunset Blvd as the major north-south traffic artery through the district.  It is important as the only wind break in the windiest district of the city, which is only 13 short blocks from the ocean.  The district is virtually treeless because of wind conditions and the pre-settlement landscape of barren sand.  Sunset Blvd is therefore the oasis of the Sunset District.  In the past, it was the only place to take a long walk in the shelter of the tall Monterey pines and cypress and tall-shrub understory.  The lawn beneath the trees was the only place for children to play close to their homes.

San Francisco’s Department of Public Works (DPW) is responsible for maintaining the medians in San Francisco.  It was therefore DPW’s responsibility to replace the wind break on Sunset Blvd that is dying of old age.  That’s not what they chose to do.  They are replacing the lawn with native shrubs and the tall trees with small native trees that won’t provide shelter from the wind. 

The spokesperson for DPW acknowledged that the project is controversial.  Neighbors of Sunset Blvd valued the sheltered recreational space provided by the 2.5 mile-long and wide median.  Native plant advocates and their allies want to create a wildlife corridor through the western edge of the city.  The spokesperson for DPW said that their plans are a compromise between these different viewpoints.  I don’t know if the neighbors agree, but I can say that native plant advocates are thrilled with the new native plant gardens on Sunset Blvd based on their presentation at the CNPS conference.

Planting Sunset Blvd. with native plants, December 2020

Native plant advocates prevailed on Sunset Blvd because CNPS bought or raised all the native plants and provided volunteers to plant them and maintain them for 3 years.  DPW couldn’t look their gift horse in the mouth. DPW hired 6 new gardeners to support maintenance of Sunset Blvd. This is an example of how the money that is flowing into such projects will transform many places into native plant gardens. 

Sunset Blvd and Taraval, spring 2022

So, let’s look at the result of these projects.  Presenters of these projects showed many beautiful pictures of newly planted native gardens on Sunset Blvd (above).  The pictures were taken in spring, when native plants briefly flower.  But that’s not what these places look like most of the year.  They will look better if they are irrigated year-round, but that would defeat the purpose of replacing the lawn to reduce water usage.  Unlike native plants, lawn turns brown during the dry season if it isn’t watered, but it is still functional as walkable ground. 

Here’s what that garden at Sunset Blvd and Taraval looks like most of the year:

Sunset Blvd & Taraval, October 23, 2022

There was also a presentation by a spokesperson from San Francisco’s Public Utilities Commission (PUC) about the creation of rain gardens in San Francisco.  San Francisco’s sewer system was built long ago when regulations did not require the separation of street run off from residential sewage.  When it rains, the sewage treatment plant is overwhelmed by street run off.  The sewage treatment plant releases untreated sewage and run off into the ocean, in violation of federal standards for water treatment. 

Rain garden on Sunset Blvd as shown at the CNPS Conference
Rain Garden on Sunset Blvd in August 2022. They aren’t pretty year around.

The PUC is developing rain gardens to redirect street run off away from sewage treatment plants into the ground so that treatment plants are not overwhelmed during heavy rain.  The San Francisco Chronicle recently reported that 151 rain gardens have been installed so far. It seems a very good idea, but native plant advocates are not happy with the rain gardens because the PUC has not made a commitment to plant exclusively native plants in the rain gardens.  The audience pressured the speaker about this issue.  He advised them to lobby the PUC to make a commitment to plant only native plants in the rain gardens.  I have no doubt that they will take his advice.  Given their influence and their access to public funding, I would be surprised if the PUC continues to resist their demands.

Conclusion

I have undoubtedly exhausted your patience, although there is much more I could tell you about, including several projects that look promising because they are exploring the importance of soil health to achieve successful results.

The conference themes in 2022 were consistent with the previous two conferences I have attended since 2015.  This is my summary of the fundamental errors of the nativist agenda in the natural world.  They are as apparent in 2022 as they were in 2015: 

  • The futility of trying to eradicate non-native plants that are better adapted to current environmental conditions.
  • The futile and harmful attempts to prevent natural succession and hybridization.
  • The contradictory goals of fuels management and resource management.
  • The lack of understanding that vegetation changes when the climate changes.  The ranges of native plants have changed and will continue to change.  The pre-settlement landscape of the 18th century cannot be recreated.
  • The lack of understanding of the importance of soil health to ecological restoration and associated ignorance (or denial) of the damage that pesticides do to the soil. 

(1) Abstracts for all presentations are available on the CNPS website.

Bringing Botany into Medical Science

In American Eden, Victoria Johnson tells the remarkable story of an American physician, David Hosack, who brought knowledge of the medicinal properties of plants to America at the end of the 18th century.  The medicinal properties of plants have been known to humans for thousands of years, but incorporating that knowledge into modern medical science began only in the 18th century. 

Traditional knowledge of the medicinal properties of plants was closely tied to many religious superstitions.  The Doctrine of Signatures seemed a logical botanical belief at a time when plants were one of man’s few medicinal tools and religion was a powerful influence in human society.  The Doctrine of Signatures, which was actively promoted by the church in 17th century Europe, was based on a belief that God had “signed” plants with certain suggestive shapes and colors to inform humans of their medicinal properties.  For example, a heart-shaped leaf was considered God’s message to us that a particular plant would be beneficial to the human heart and this message was strengthened by a flesh-colored flower. Every plant was believed to be useful in some way if man could only discern its use.  Else why would they have been created, since the Garden of Eden was created for the benefit of man?  The church encouraged man’s study of plants as a way to worship God’s creation. (2)

David Hosack

Medical science was equally burdened with harmful, often deadly, medical practices such as bleeding and prescribing mercury.  When David Hosack began practicing medicine in New York at the end of the 18th century he was acutely aware of the limitations of the tools of his profession.  He could see the promise of prescribing plant extracts to his patients, but he was frustrated by his limited knowledge of plants, their uses and his access to them. 

He decided that learning more about botany and horticulture were the prerequisites for developing the medicines his patients needed.  He went to England and Scotland where he studied for two years under the tutelage of the pioneers of the botanical science that was beginning to transform medicine. 

The development of the Linnaean system of classifying species earlier in the 18th century enabled a more systematic study of plants based on their close relationships and similarities.  Physicians and apothecaries had for centuries relied on inaccurate rules to try to divine the medicinal properties of specific plants.  Medicinal properties cannot be determined by a particular color, shape, or smell.  Linnaeus’s new framework classified plants into orders, classes, families, genera, and species, groups with similar medicinal properties because they were chemically similar.  Plants in the same order were expected to share some of the same medical properties.  Plants in the same class share more properties, families still more and the most similarity is found within a genus. “By way of example, Linnaeus noted that the various known species of Convolvulus, a genus in the bindweed family that included morning glories, all appeared to have purgative effects on the body.” (1) 

In Scotland and England the knowledge of the medical uses of plants and the classification of plants according to the Linnaean system led to the development of botanical gardens where new plants with these properties could be studied and medical students were taught to identify the plants and learn their medical uses.  These botanical gardens enabled the incorporation of botanical knowledge into medical knowledge.  The gardens collected plants from all over the world that were recognized as the close relatives to plants from closer to home and were considered equally valuable as potential therapeutic drugs. 

These botanical gardens fostered a cosmopolitan view of plants that actively sought and welcomed new plants from the regions of the world that were being newly explored.  The Linnaean classification system made it possible for new plants to be incorporated into the global family of plants.  We have lost this sense of a global family of plants.  Instead of classifying plants according to their membership in families, orders, and classes, the plant world has been artificially divided into two meaningless categories:  native and non-native.  These categories prevent us from understanding the close relationships between plants.  The native plant movement has turned most of the plant world into aliens. Just as dividing the human race into white and non-white is prejudicial and harmful, dividing the plant world into native and non-native is equally pernicious.

The Consequences of Putting Plants into “Native” Strait-Jackets

Milkweed is an example of the consequences of classifying plants based on their native status.  There are about 200 species of milkweed in the Asclepias genus and they are distributed broadly across Africa, North America, and South America.  There are a few species of milkweed native to the Bay Area, but the most popular species of milkweed, tropical milkweed (Asclepias curassavica), is not.  It is popular with home gardeners because it is a strikingly beautiful plant and it is evergreen, unlike our native milkweed, which is deciduous, therefore not available in winter months.

Monarch butterflies are dependent upon milkweed as its host plant.  They lay their eggs on milkweed and their caterpillars eat milkweed.  In the past, monarchs in California spent the winter roosting in trees along the coast of California.  They did not breed during the winter.  They moved inland during summer months where they bred.

Because of global warming, monarchs have begun to breed during the winter months in California and the existence of tropical milkweed in gardens in coastal California has made that possible:  “the [monarch] population boom in the Bay Area had not been seen before.  It was unusually warm that fall, which may have accounted for the numbers.  And tropical milkweed, which unlike native milkweed flowers through the winter and creates a suitable habitat for breeding, was abundant in gardens.” (3)

Scientists with a commitment to the survival of monarchs have welcomed this development:  “But the growth of local, breeding monarchs is seen, at least by some, as a sign of the resilience of the monarchs, their ability to find new ways to persist in the face of an increasingly threatened migration.  Might we be seeing the growth of a resident population of monarchs in the Bay Area?” (3)

The Nature Police have succeeded in getting the sale of tropical milkweed banned in Contra Costa, Marin, San Mateo and Ventura counties.  Academic entomologist have pushed back against this harmful ban in an article published by The Monterey Herald, San Jose Mercury, Marin Independent Journal, and East Bay Times:

  • “Hugh Dingle, a retired University of California at Davis entomology professor who has studied monarch butterfly migration for more than two decades, said the bans are “basically a wasted effort” and that the focus should be on larger threats such as pesticide and herbicide use. All species of milkweed carry parasites that can affect monarch populations, Dingle said.”
  • “Arthur Shapiro, a UC Davis professor who has studied monarch butterflies for the past six decades, described the rationale behind the bans as “hogwash.”  Shapiro, Dingle and other researchers said winter breeding among monarch butterflies is a relatively new behavior and one influenced by warmer winter temperatures caused by climate change.”
  • “David James, an associate entomology professor at Washington State University who has studied monarch butterfly breeding and migration in the Bay Area, said there is a case to be made about the tropical milkweed as being a vital resource for the monarchs in a changing climate.”
  • “Leslie McGinnis, a UC Berkeley doctoral candidate studying monarch populations and working with gardeners in the East Bay, said the bans take a “simplistic view” of the threats that monarchs face, including the fact that many native milkweed plants supplied to nurseries can also be sprayed with pesticides. The bans, she said, can work to disenfranchise or demonize people that have tropical milkweed who instead could be partners in working to help restore monarch populations.”

Native plant advocates are wedded to a past that is long gone.  The climate has changed and it will continue to change. Monarchs and other animals are trying to adapt to the changed conditions.  Their survival depends on their ability to adapt.  The native plant movement has become a form of climate change denial.  Their irrational hatred of introduced plants is damaging the environment with herbicides and harming wildlife. There is no evidence that tropical milkweed is harmful to monarchs.

Update:  Professor Art Shapiro has kindly offered this addition to the many benefits of tropical milkweed, which is also a reminder that both native and non-native plants often have medicinal properties:  “Asclepias curassavica is known as “cancerillo” in rural Latin America and a root extract is reputed to have anti-cancer properties. It has a huge number of ethnobotanical uses. Because steroid cardenolides are highly toxic, it should not be used except under the guidance of an expert herbalist. I do not know if the alleged anti-cancer activity has been formally investigated. Virtually every rural peasant I have asked about it in Colombia, Mexico, Peru, Argentina and Chile knows its reputation.”  Thank you, Professor Shapiro, for this useful information.  Professor Shapiro has traveled widely in Latin America to visit his butterfly friends.  October 1, 2022

Elgin Botanical Garden

David Hosack studied under the tutelage of the botanical pioneers in England who taught physicians how to use plants to treat their patients.  When he returned home in 1794 he was determined to establish a botanical garden in New York that would be available to medical students at Columbia College, where he taught.  The botanical garden was needed to collect plants from all over the globe, including the unsettled regions of the new nation.  That was his life’s work.

Hosack began his venture by trying to convince Columbia College that a botanical garden was needed to educate physicians and supply them with the medicines they needed for their patients.  It was his intention to collect plants from all over the world to study their medicinal properties and make more therapeutic remedies available to physicians and their patients. Every plant in the world was potentially useful in his opinion. He named the garden Elgin Botanical Garden after his father’s home town in Scotland.

Elgin Botanical Garden, 1810

When Hosack was unable to convince Columbia College to make this investment for their medical school, he built the garden himself at his expense.  He also tirelessly recruited plant specimens from all over the world.  Although he built a world-class institution, he was draining his personal resources.  He tried and eventually convinced the State of New York to buy the garden from him.  The State acquired the garden, but did not provide for its maintenance.  Hosack lost control over the management of the garden and it was quickly gutted by unscrupulous managers who sold the collection for personal gain.  The garden was in ruins when Hosack died in 1835.  The garden is commemorated by a small plaque on the Rockefeller Center that occupies the ground where the Elgin Botanical Garden was built. 

The Historical Context

The story of David Hosack’s extraordinary accomplishments takes place within the context of early American history.  Hosack knew every major player in American politics, government, literature, science, and business.  He was personal friends with both Alexander Hamilton and Aaron Burr.  He was asked by Hamilton to attend the duel with Aaron Burr and he attended his death after the duel in 1804.  Hosack had strong feelings about the obligations of physicians to remain neutral in all political matters.  Although he had a strong affection for Hamilton, he maintained his friendship with Aaron Burr until his death.  Burr’s sad story appears many times in American Eden, as he descends into a life of obscurity because of his role in Hamilton’s death, a choice he is said not to have regretted.

Many other important people appear in the story as Hosack befriends them and often plays a role in their success.  Napoleon Bonaparte’s botanist is among those who revered Hosack.  When Napolean sent him to America to collect new plants, Hosack took him under his wing.  He studied plants at the Elgin Botanical Garden while earning his degree as a physician.  Hosack and Alire Raffeneau Delile had a life-long correspondence.  Hosack’s son, Dr. Alexander Hosack, visited Delile in France after his father’s death.  Delile recognized him instantly as Hosack’s son and embraced him warmly.  He showed Alexander Hosack his prized possession, his long correspondence with David Hosack. 

David Douglas, the Scottish botanist who named many American native plant species during his expeditions in America was a friend of Hosack.  Douglas visited California where he named Douglas fir and Douglas iris, among others.  Douglas studied with Hosack and later acknowledged his importance to American botany by naming a new genus of wildflower he found in the Western US Hosackia, as a tribute to his favorite American.

Hosackia oblongifolia

American Eden is a rewarding book for many reasons, including an intimate glimpse into the lives and events of early America.  It is also a reminder of the heavy price of botanical ignorance that is relevant to the horticultural controversies of today.


  1. American Eden:  David Hosack, Botany, and Medicine in the Garden of the Early Republic, Victoria Johnson, W.W. Norton & Company, 2018
  2. Weeds:  In Defense of Nature’s Most Unloved Plants, Richard Mabey, Profile Books Ltd, London, 2010
  3. “The Story of the Butterflies,” Endria Richardson, Bay Nature, Summer 2022

Tale of Two Butterfly Gardens

We visited two butterfly gardens on a recent trip to Santa Cruz.  The two gardens take different approaches to providing butterflies with what they need.  The different strategies contrast the nativist approach with an approach that emphasizes diversity.  The more diverse approach seems to be more successful in attracting butterflies, at least in the case of these two gardens that are located within a few miles of one another, in very similar climate conditions.

Natural Bridges State Park is the home of a eucalyptus grove that provides shelter for overwintering monarchs from November to February.  Only 550 monarchs roosted in the trees in November 2020.  The population of migrating monarchs in California increased greatly in 2021 and the site at Natural Bridges was no exception.  2,100 monarchs were counted at Natural Bridges in November 2021.  

Signs explain why eucalyptus trees provide the ideal shelter for overwintering monarch butterflies.  They shelter the butterflies from wind and rain.  Their canopies are open to the sunlight that provides the heat needed to keep the monarchs active and able to feed.  Eucalyptus are blooming when the butterflies are roosting, providing the nectar the butterflies need to sustain them.

Remarkably, signs also inform visitors that other non-native plants, such as English ivy, provide monarchs with the food they need to live through the winter months:

Natural Bridges State Park also puts its money where its mouth is.  Rangers have installed a butterfly garden in front of the ranger station that is an eclectic mix of native and non-native plants.  Many are non-native favorites of butterflies, such as Buddleia (butterfly bush), cosmos, and Scabiosa (pin cushion flower).  Both Buddleia and Scabiosa have been designated as “invasive” by the California Invasive Plant Council and are eradicated with herbicides by many public land managers.   Natural Bridges State Park seems to be an exception to that unfortunate rule, possibly because they have observed what butterflies actually use and need.

Butterfly garden, Natural Bridges State Park, Santa Cruz

Proving that point, here is an Western Tiger swallowtail butterfly nectaring on Scabiosa at Natural Bridges.

The Flip Side:  UC Santa Cruz Arboretum and Botanic Garden

The second butterfly garden we visited was in the UC Santa Cruz Arboretum and Botanic Garden, just a few miles away from Natural Bridges State Park.  The butterfly garden at the UCSC botanic garden is exclusively native and the narrative on its signs is consistent with the nativist agenda:

There isn’t much blooming in July in a garden of exclusively California natives.

No monarch butterflies were observed in the UC Santa Cruz Arboretum and Botanic Garden during their 2021 California migration.

The UCSC botanic garden is well worth a visit.  Its focus is the flora of Mediterranean climates:  California, South Africa, Australia, and New Zealand.  The garden is an opportunity to observe that many of our favorite plants come from other Mediterranean climates and observing them in July helps us to understand that planting a diverse, drought-tolerant garden can provide year-around blooms for pollinators and add color to our own gardens:

There’s not much blooming in the California section of the UCSC botanic garden in July.
Protea in the Australian section of the UCSF botanic garden is blooming like mad in July.
This is Bushy Baeckea from Australia, also flowering profusely in the USCS botanic garden in July.
This is the New Zealand section of the UCSC botanic garden.  “Electric Pink” (Cordyline australis) provides the color in this garden.  Our motel in Santa Cruz was landscaped with this stunning plant.

What does the tale of two butterfly gardens tell us?

I hope these pictures speak for themselves, but in case they don’t here’s the point of this post:

  • Butterflies and other pollinators do not care where plants are from.  They are looking for food and shelter.  If non-native plants provide what they need, they will happily use them.
  • Non-native plants from other Mediterranean climates are well-adapted to our climate.  They are also drought-tolerant. 
“Electric Pink” Cordyline australis captures the morning dew on its spikey leaves and funnels the moisture to the roots of the plant.  This is an adaptation to a dry climate. 

Pesticide use in public parks in the San Francisco Bay Area

San Francisco Forest Alliance (SFFA) is a 501(c)4 not-for-profit organization with a mission of inclusive environmentalism. SFFA fights to protect our environment through outreach and providing information. SFFA opposes the unnecessary destruction of trees, opposes the use of toxic herbicides in parks and public lands, and supports public access to our parks and conservation of our tree canopy.

With permission, Conservation Sense and Nonsense is republishing SFFAs annual report on pesticide use by San Francisco’s Recreation and Park Department.  The report separates pesticide use in so-called “natural areas” from other park areas and finds that most pesticides are used in “natural areas.”  Conservation Sense and Nonsense is grateful to SFFA for compiling and reporting this important information. 

Conservation Sense and Nonsense follows pesticide use by the East Bay Regional Park District (EBRPD), where the pattern of pesticide use is similar to San Francisco’s Recreation and Park Department.  EBRPD has restricted spraying of glyphosate pesticides in developed areas of the park while continuing to use pesticides in naturalized areas to eradicate non-native plants.  In other words, most pesticide use in the public parks of the San Francisco Bay Area is devoted to eradicating non-native plants.

Conservation Sense and Nonsense


As we usually do, we compiled the pesticide usage data for San Francisco Recreation and Parks Department for 2021.  (We exclude Harding Park – but not the other golf courses – from this analysis because it’s externally-managed under a PGA contract to be kept tournament-ready at all times.) We’re pleased to note that SFRPD has reduced its pesticide usage in comparison to 2020 and 2019. 

NATIVE PLANT AREAS USE MORE OF THESE TOXIC HERBICIDES

But this is not true of the Natural Resources Division (this includes PUC areas managed in the same way – i.e. use of toxic herbicides against plants they dislike). Their usage has risen and is the highest it’s ever been from 2016.

The Natural Resources Department (NRD, formerly the Natural Areas Program or NAP) is the entity that is trying to bring “native” plants to more than a thousand acres of our parks, cuts down trees and restricts access to people and their pets.  NRD, which accounts for perhaps a fourth of the land area, used over 70% of the pesticides measured as active ingredients in fluid ounces.

NRD – and PUC lands that they are managing the same way – continued to increase their use of triclopyr since the new pesticide Vastlan has been designated Tier II (More Hazardous) instead of Garlon, which was Tier I (Most Hazardous). In both herbicides, the active ingredient is triclopyr. They also increased their usage of imazapyr, and continued to use Roundup, though in smaller quantities than before.

Here are the two earlier graphs lined up to show the comparison. The Native Plant areas used more herbicides in 2021 than they had ever used in the last six years – or that the other SFRPD departments together used in the same time. Their failure to reduce usage in 2021 is in stark contrast to the more than 50% drop in the other SFRPD.


SFRPD Other (i.e. other than the Native plant areas) uses mainly Polaris (imazapyr) and Clearcast ( ammonium salt of imazamox). The native plant areas, NRD / SFPUC, use large amounts of triclopyr, (Garlon and Vastlan), as well as some glyphosate (Roundup).

A FAILING STRATEGY

The NRD’s continually growing usage of the herbicides is a sign that this strategy is failing. They have been using hazardous chemicals on some 50 target species of plants year after year. Theoretically, the point of using toxic herbicides on unwanted species is to allow the desired species to replace them.  Instead, the growing usage of these chemicals shows that if anything, the situation is only made worse.

This stands to reason; “invasive” plants are successful because they are better adapted to current conditions. If they are destroyed with herbicides, the replacement is likely to be the next best adapted (thus, invasive) species. Given 50 target species, the bench is deep. This leads to a vicious cycle of hazardous herbicide use, clearly visible in the graph above.

PESTICIDES COME TO SHARP PARK 

For many years since we started compiling these data, Sharp Park has been off-limits for pesticides. We’ve seen very minimal usage – maybe 3 or 4 times over all the years. It’s home to the red-legged frog, and the San Francisco garter snake.

In 2021, that changed. In the space of one year, pesticides were applied 9 times. We did anticipate this would happen as NRD extended its grip on this park.

TIER HAZARD RATINGS

San Francisco’s Department of the Environment (SFEnvironment) assigns Tier hazard ratings to the various pesticides it uses. Tier III is Least Hazardous, Tier II is More Hazardous, and Tier I is Most Hazardous.  Over the years we have been following this usage, we have seen various chemicals being moved from one Tier to another. Milestone was moved from Tier I to Tier II; Glyphosate (Roundup, Aquamaster)  from Tier II to Tier I; and triclopyr (Garlon, Garlon 4 Ultra, Turflon, Vastlan) from Tier I to Tier II (for Vastlan and Turflon). Avenger was moved from Tier II to Tier III, which we think makes sense and makes analysis easier. We analyze the usage of Tier I and Tier II herbicides.

REDUCE OR ELIMINATE HERBICIDE USE

SF Forest Alliance has been trying to encourage SFRPD to reduce or eliminate Tier I and Tier II herbicide use. Some years ago, it appeared that pesticide usage was declining, especially after the Roundup revelations. When we wrote our Pesticides report for 2016, the other areas of SFRPD had slashed their herbicide use; the NRD accounted for 74% of pesticide usage. The 2021 data have renewed our hope that SFRPD’s other departments will adopt a cautious approach to the use of toxic herbicides. Unfortunately, this does not appear true of the nativist departments, NRD / PUC.


Every year, the San Francisco Forest Alliance also makes public comment at the annual review of San Francisco’s Integrated Pest Management program.  Conservation Sense and Nonsense is grateful for SFFA’s vigilance of pesticide use in San Francisco’s public parks.  Below is an excerpt from SFFA’s public comment to the Commission on the Environment regarding San Francisco’s IPM program.

Conservation Sense and Nonsense


Once again we are sending our comments emphasizing the self-evident truth that high toxicity herbicides are dangerous, unnecessary, and should never be used…

Below are the points we have repeated year after year for many years:

  • Herbicidal chemicals are more toxic, more persistent, more mobile and more dangerous than their manufacturers disclose;
  • The aesthetic or ideological “danger” from “weeds” is not a risk to health and welfare;
  • Scientific studies associate exposure to herbicides with cancer, developmental and learning disabilities, nerve and immune system damage, liver or kidney damage, reproductive impairment, birth defects, and disruption of the endocrine system;
  • There is no safe dose of exposure to those chemicals because they persist in soil, water, and animal tissue, so even low levels of exposure could still accumulate and harm humans, animals, and the environment;
  • Especially vulnerable individuals include infants, children, pregnant women, the elderly, people with compromised immune systems and chemical sensitivities;
  • Toxic runoff from herbicides pollute streams and groundwater, and therefore the drinking water sources;
  • Herbicides are harmful to pets and wildlife – including threatened and endangered species, plants, and natural ecosystems;
  • Herbicides are harmful to soil microbiology and contaminate soil into the future, reducing biodiversity in sensitive areas…

San Francisco Forest Alliance, July 11, 2022

Creating Tree Graveyards in San Francisco

At 13.7% of tree canopy coverage, San Francisco has one of the smallest tree canopies of any major city in the country.  When San Francisco’s Urban Forestry Council (UFC) announced its goal of planting 30,000 new street trees in the next 20 years, it seemed a modest goal.  Yet, Jake Sigg, the leader of native plant advocates in San Francisco, immediately objected to even this modest goal in his Nature News.  He announced the meeting of the UFC to consider the proposal and pronounced it a bad idea:

“JS:  Let’s start taking climate change seriously.  There is a prejudice—it is nothing more than that—that trees sequester more carbon than other life forms.  That is a simplistic view that, when looked at more closely, is found wanting.  To counter climate change we need to remove carbon from the air and put it where it will be for a millennium or more.  Removing it for a few decades or a century is pointless. 

“There are many reasons to plant trees on San Francisco streets, and many of our streets need them.  Climate change is not a stand-alone phenomenon; it is intimately related to diversity of biological elements.  That argues for planting native plants to invite dispossessed wildlife back into the city and you do that by planting the plants they need.  There are trees, shrubs, and perennials that ought to line our street to function in this way.  Carbon removal should not be a factor in our street plantings—biodiversity should be Number 1.”

Jake Sigg, Nature News, July 2, 2022

Yes, Jake, biodiversity is important because a diverse ecosystem is more resilient in a changing climate, but destroying all non-native plants does not make an ecosystem more diverse.  Climate change is the greatest long term threat to biodiversity, which makes addressing climate change a prerequisite to preserving biodiversity. 

I attended the Urban Forestry Council meeting of July 5, 2022, when this proposal was considered.  I was expecting to hear objections from Jake Sigg’s followers. Instead, the handful of written public comments objected to the meager commitment to plant only 30,000 new trees in San Francisco in the next 40 years. I learned more about the plan to plant more street trees in San Francisco:

  • There are presently an estimated 125,000 street trees in San Francisco.
  • Because the mortality of street trees is high, the expectation is that 50,000 street trees would need to be planted in the next 20 years to replace dead street trees.
  • According to the Urban Forestry Council it costs $1,500 to plant a tree and an additional $2,500 to water it for three years until it is established.
  • 4,000 trees would need to be planted every year to keep pace with expected tree mortality and to add 30,000 more street trees. 

These goals exist only on paper.  Between 1,500 and 2,000 trees per year are being planted in the city and no funding has been identified to increase this number.  After delivering this bad news about the sorry state of San Francisco’s urban forest, one member of the UFC spoke some much needed common sense.  Nicholas Crawford said we should “hold onto shabby trees” that are established and storing carbon.  He suggested that San Francisco should not remove trees that are at least stable because there are no trees to replace them. 

Existing trees in our urban forest are more valuable than ever.  They are storing more carbon than a replacement tree will store for at least 20 years.  They don’t need to be irrigated because they have the root and fungal networks needed to supply the tree with the moisture it needs.  Existing trees have proven themselves.  The fact that they are alive and well after 10 years of extreme drought proves they are adapted to current climate conditions.  So why destroy them? 

Jake Sigg acknowledged the value of forests to address the challenges of climate change in a recent newsletter:  “In order to have an impact on climate we need to stop deforestation and preserve, strengthen, and restore what is already here.” (Nature News, July 6, 2022)  But that principle does not apply to San Francisco for Sigg and his followers because the trees of San Francisco are predominantly non-native and they place a higher value on restoring pre-settlement treeless grassland and coastal scrub.  Because of the power and influence of the native plant movement in San Francisco our urban forest is being destroyed and planting trees is resisted.

San Francisco has made a commitment to destroying more than 18,000 non-native trees in San Francisco’s public parks.  The stated goal of that program is a landscape of native grassland and scrub.  UC San Francisco has also made a commitment to destroy most of the non-native forest on Mount Sutro.  Thousands of trees have been destroyed on Mount Sutro and more will be destroyed in the future.  The Executive Director of Sutro Stewards, the non-profit organization that is implementing the plans for destruction of the non-native forest on Mount Sutro is represented on the Urban Forestry Council, an odd choice for a citizen’s advisory council theoretically committed to the urban forest.

Tree destruction on Mount Sutro, January 2021.  Courtesy San Francisco Forest Alliance

McLaren Park:  A Case Study

Today Conservation Sense and Nonsense will visit a relatively new project in McLaren Park that has destroyed non-native trees in order to create a small native plant garden.  We drill down into the project to understand why San Francisco’s urban forest is being destroyed.  We visit this project because it is an example of many similar projects that are planned in San Francisco. 

This is one of many attempts to plant native plant gardens on Sunset Blvd in San Francisco. The functional windbreak of Monterey cypress is dying of old age. Rather than replace the windbreak, native shrubs are being planted on Sunset Blvd that will not function as a windbreak in the windiest district in San Francisco. The lack of maintenance that you see here is typical of these gardens, which makes them unpopular with neighbors.

At 312 acres, McLaren Park is one of the largest parks in San Francisco.  Fifty-three percent (165 acres) of McLaren Park is designated as a “natural area,” which means that a commitment was made nearly 25 years ago to transform it into a native plant garden.  The new native plant garden that we visit today is not actually inside one of the designated “natural areas.”  The reach of the native plant movement in San Francisco extends far beyond the 1,100 park acres of “natural areas” that were claimed in 1998. 

The new native plant garden is located in the southeast corner of McLaren, south of the community garden at the intersection of Visitation Ave and Hahn St.  This is a photo of some of the trees that were destroyed to create the native garden:

©Lance Mellon with permission.  July 2020

And this is a photo taken in December 2021, after the trees deemed “non-native” were destroyed:

© Lance Mellon with permission

The plans for the native plant garden say that 18 non-native trees would be destroyed and 6 native trees would be retained.  The plan claims that tree removals of all non-native trees were based on “professional assessments.”  Such “assessments” are routinely used by the Recreation and Park Department to justify the removal of non-native trees.  Photos of the trees indicate otherwise.  Retention of only native trees suggests that assessments aren’t even-handed.  The claim does not pass the smell test. 

Plans for the native plant garden indicate that more native trees will be planted:

The trees will need to be irrigated for at least 3 years to establish their root systems and ensure their survival.  The entire garden will need to be irrigated if it is to survive.  Let’s be clear:  an established grove of trees with an understory of annual grasses that did not require irrigation or maintenance was destroyed and replaced with new plants and trees that will require irrigation.  Is that a suitable use of scarce water resources during an extreme drought that is expected to get worse, if not be a permanent change in the climate?  That is the question we consider today.

About 9 months later, the “native plant garden” looks more like a tree graveyard:

McLaren Native Plant Garden, July 2022
Some of the newly planted trees are holly leaf cherry. Signs on the trees indicate that the project was paid for with a CAL FIRE grant. One wonders how a garden full of dead wood is less flammable than a garden full of living trees.

Granted, the native plant garden is likely to look better as plants grow.  However, it will only look better if it is irrigated and taken care of.  Why should we expect it to be taken better care of than the existing garden that required no maintenance?  Wishful thinking will not make it so.

The death grip of nativism

Climate change is the environmental issue of our time.  We are seemingly incapable of doing anything substantive to address climate change.  Political gridlock prevents us from controlling the greenhouse gas emissions causing climate change.  The Supreme Court recently ruled that the Environmental Protection Agency does not have the authority to regulate polluting emissions from power plants. 

We focus on the preservation of our forests because it is the only tool we have left to absorb carbon emissions from the fossil fuels to which we are wedded.  Native plant advocates have taken that tool away from us.  Our urban forests are being destroyed and replaced with grassland and scrub.  Claims that grassland and scrub store more carbon than forests are ridiculous.  Those claims earn native plant advocates the label of climate change deniers.  As the drought continues to plague California, established landscapes that required no water are being destroyed and replaced with native plants that require irrigation.