Drawing from a book by Andrea Wulff (1), we recently told our readers about the enthusiasm of the British for exotic plants from all over the world, particularly American plants. Andrea Wulff has recently published a second book (2) which informs us that while American plants made the journey to Europe, this botanical transfer was not reciprocated by early Americans.

Our founding fathers were reluctant politicians, but devoted gardeners and professional farmers. Although they grew many non-native plants for food and other practical purposes, they used almost exclusively American trees and shrubs when landscaping their properties. The historical record suggests that this was a conscious choice on their part and a reflection of their patriotism.
Although George Washington was able to visit his home at Mount Vernon only once during the eight-year Revolutionary War, his correspondence suggests that it was always much on his mind. As the city of New York prepared for the onslaught of British troops and warships in 1776, Washington wrote to his estate manager by candlelight, “Only American natives should be used, he instructed, and all should be transplanted from the forests of Mount Vernon…Washington decided that Mount Vernon was to be an American garden where English trees were not allowed.”
As a farmer, Washington was innovative and practical. He experimented with various methods of fertilizing and crop rotation. He imported food crops and fruit trees from all over the world. But when landscaping for ornamental purposes, he planted exclusively American plants which “…carried a symbolic message that this new nation would be independent, self-sufficient and strong.”
Shortly after Americans won their independence from Britain, our second and third presidents, John Adams and Thomas Jefferson, went to Britain hoping to negotiate a trade treaty with their former rulers. This was a frustrating and ultimately unsuccessful effort, but while waiting in vain for a response to their proposal, Adams and Jefferson toured many of the famous gardens of England. They were both avid gardeners and farmers and could think of no better use of the idle time imposed upon them. They were proud to learn that the most lavish private gardens of England were composed predominantly of American trees and shrubs. As we reported in our earlier post, these plants had been laboriously imported to England earlier in the 18th century.
Returning home, their horticultural choices were similar to Washington’s. They made utilitarian choices when farming, but their ornamental choices were exclusively American.

Jefferson brought vegetable seeds from all over the world to his vegetable garden. He kept meticulous records which enable us to marvel at the international population of vegetables in his garden during the first year of his retirement from the presidency: “African early peas,” “Windsor beans,” “solid pumpkin from S. America,” “long pumpkin from Malta,”, “Lettuces Marsailles,” “Chinese melon,” “Spanish melon,” “Broccoli Roman,” “Kale Malta,” “Kale Delaware.”
As the first American president to spend his entire term in residence in the White House (actually not yet named the White House), he was responsible for designing its first landscape: “He envisaged an all-American garden…planted ‘exclusively with Trees, shrubs, and flowers indigenous to our native soil.’” When returning home to Monticello, he made the same ornamental choices for his own property.
Peter Coates, a British historian, examines the historical record of American fears regarding non-native species of plants and animals in his book, American Perceptions of Immigrant and Invasive Species (3), looking for a relationship between nationalism and those fears. Although he finds many examples of similarity in the language used to describe human and non-human immigrants, he ultimately concludes that human xenophobia is not necessarily the source of anxiety about non-native plants and animals.
One of the episodes in the historical record which Coates reports, is a long correspondence between Charles Darwin, the British scientist and his American counterpart, Asa Gray. They engaged in a chauvinistic rivalry about the hardiness of their native plants. Darwin jokingly asked, “Does it hurt your Yankee pride…that we thrash you so confoundedly? I am sure Mrs. Gray will stick up for your own weeds. Ask her whether they are not more honest, downright good sort of weeds.” Gray replied that his wife, “allows that our weeds give up to yours,…[they are] modest…retiring things, and no match for the intrusive, pretentious, self-asserting foreigners.”
In this exchange, Darwin and Gray are referring to a botanical conundrum: “The asymmetry between the preeminence of Eurasian weeds in North American and the weak presence of North American weeds in Eurasia has engrossed botanists on both sides of the Atlantic since Darwin and Gray’s exchanges.” (3) It is an intriguing question which we have considered in earlier posts, but cannot answer.
The historical record suggests that there is an element of patriotism in Americans’ preference for our native plants and trees. On the other hand, maybe our plants and trees are just more handsome! But when plants perform a function—such as feeding us—Americans revert to their utilitarian ideals, abandoning natives if introduced plants are superior.
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(1) Andrea Wulff, The Brother Gardeners, Alfred A. Knopf, 2008
(2) Andrea Wulff, The Founding Gardeners, Alfred A. Knopf, 2011
(3) Peter Coates, American Perception of Immigrants and Invasive Species, UC Press, 2006.
I have a preference for natives because they are hardier and look better (in Sonoma County). There are some East Coast trees that look good on the East Coast but not as good here and require more effort to grow and maintain. And the Japanese pines in the Royal Garden in Tokyo look great there but not in my yard. However, as you pointed out, trees in SF are another matter. There are hardly any SF native trees and I notice that foresters use alien species for street trees; probably because they are hardier?
From the file you can’t fool Mother Nature comes weeds that adapt to weed killers: http://e360.yale.edu/feature/the_folly_of_big_agriculture_why_nature_always_wins/2514/
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You’re right about the trees of San Francisco. There were few native trees in the San Francisco Bay Area prior to the arrival of Europeans. They grew only in the crevices of the hills where they were sheltered from the wind and water was funneled to the them by the hills. They are all trees of short stature which grow close to the ground so they are not useful as street trees.
Any trees are better than no trees. I’m glad the point about “no native SF trees” has been made – San Francisco was barren and sand-whipped. I’ve read numerous historical docs mentioning how awful was the wind and sand and treeless landscape. Much more beautiful now!
Not only that, because of climate changes, even native CA trees are dying. So we need to keep all trees that are making it in this climate. Just because something flourished here hundreds of years ago doesn’t mean it will flourish now.
In the 4th Grade lesson below on San Francisco history, (on all pages) there is nary a tree in sight. We are fortunate to now have Sutro Forest and the other wonderful stands of trees, as well as street trees to soak up the pollution in San Francisco. Compared to other US cities, however, we really need more trees to catch up.
http://museumca.org/goldrush/curriculum/4g/41202026.html
Because of climate change native trees and non-native trees are doing better. Global warming plus a little more precipitation during the past 150 years has increased biodiversity. The benefit of heat was recently discussed in a study in NYC.
http://www.earth.columbia.edu/articles/view/2967
200 years ago we were just coming out of the Little Ice Age. The SF Climate would have been colder. With global warming plus the urban heat island effect trees grow better than they would have. To more closely replicate SF conditions 200 years ago and restore nature like it was then, we would need to tear down all the buildings and remove all the asphalt and cement. But even then we would need to have some global cooling.