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.
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:
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:
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.