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Editor's note: You can listen to the conversations referenced in this article, plus many more ecologically minded interviews, in episodes of author Thomas Christopher's Growing Greener podcast. This article first appeared in Horticulture's November/December 2020 issue.
In April 2020, I had the privilege of interviewing for my podcast, Growing Greener, Uli Lorimer, the Director of Horticulture for The Native Plant Trust in Framingham, Massachusetts. In a former professional incarnation, Uli was the horticulturist who expanded the Brooklyn Botanic Garden’s Native Flora Garden into a habitat-themed, world-class display. Uli was telling me about the Native Plant Trust’s practice of growing genetically diverse plants from locally sourced, wild-collected seed. I contrasted that with the push by the commercial nursery industry to transform native plants into vegetatively propagated, compact clones of no particular provenance.
Uli pointed out that the nurseries are merely supplying what they believe the customers want. Which caused me to pose a question: What if part of moving forward involves changing our concept of what a garden is? Do we need to get away from neat, purely decorative plantings to something more dynamic and fulfilling?
By dynamic, I mean something that engages more actively with the nature that we have traditionally banished from our landscapes. The alternative could be not only more fulfilling for wildlife and the ecosystem, but also for us. This is a question that’s implicit in almost every interview I record for my podcast.
I was raised in a tradition of decorative gardening, and I still want my landscape to be harmonious and visually attractive. These days, though, I want it also to be more. I want it to contribute to what Douglas Tallamy described to me as the “Homegrown National Park,” the 20-million-acre patchwork of redesigned private backyards that he hopes will come into being and return our national landscape to a healthy ecological function. (Dr. Tallamy guides us toward this goal in Nature's Best Hope.)
I am not a purist. I want there to be room in my landscape, for example, for the lovely heirloom Damask rose that a gardening friend took as a rooted sucker from an old Connecticut farmyard. There must be a spot for the dahlias that my wife loves to grow. And I’m not giving up my vegetable garden full of Old World edibles. But I plan to observe a guideline from Dr. Tallamy, that a landscape must comprise at least 70 percent native plants to serve as the basis for a working native ecosystem.
I don’t see this as a restriction. Rather, I remember what the very talented landscape architect Claudia West, co-author of Planting In a Post-Wild World, told me—that this should be a very optimistic time for gardeners. Claudia remembers growing up in the degraded landscape of communist East Germany. She watched as, after that regime fell, gardeners both public and private restored the landscape, regreening forests and fields and in the process cleansing lakes and rivers. Imagine what we can do here, with our huge resources, was her message.
Gardeners have an essential role to play in combating the environmental challenges that confront us. Climate change, for example, is warming our landscapes and changing the rules about what will grow where. Dr. Bethany Bradley, an ecologist at the University of Massachusetts, told me that the best prediction is that by mid-century the climate of central New England will resemble that of present-day Maryland. This could create an ecological disaster, displacing cool-adapted natives and turning invasive the exotic plants that we have introduced into our gardens from more southerly lands. Alternatively, though, private gardeners could take a role in what ecologists refer to as “assisted migration.” There’s nothing to stop us from introducing native plant species from warmer regions of North America, literally sowing the seeds for a native vegetation of the future.
Rewards at the Ready
There could be more immediate and selfish benefits for us in rethinking our gardens. Ecological landscape designer Larry Weaner described to me how to use the ecology inherent in your own yard to create a “self-contained garden,” one that, once set in motion, will largely plant itself. (We wrote of this together in Garden Revolution.) Careful analysis of the site, of its topography, soil and moisture, as well as scrutiny of remnants of native vegetation, will suggest what grew there before it was cleared and would therefore flourish there again if given the chance. Plant colonies of this native vegetation and encourage them to expand.
The treatment will vary with the plants, of course. Plants such as early meadow rue (Thalictrum dioicum), whose seeds are transported by the wind, may need only occasional specimens to colonize a large area. Others, such as spotted geranium (Geranium maculatum), whose seeds germinate where they fall, will need to be planted in patches throughout the area you would like it to cover.
Some plants may flourish without you planting them at all. Larry learned from a Rutgers University report that a mulch of wood chips will encourage the emergence of forest trees. Practicing this in his own yard, he was rewarded by hickory and oak trees apparently planted by squirrels. And the squirrel-planted trees grew much more vigorously, before long overtaking ones he had purchased from a nursery.
Rethinking our gardens in this fashion will bring biological richness that can be a reward to the gardener as well as wildlife. I think of Brian Stewart, whom I interviewed about his “insect a day” project. His interest in insects led him to start a collection—not of dead specimens but of portraits. Equipping his camera with a macro-lens, he went on a micro safari in the quarter-acre yard that he had planted mostly with natives. He aimed to find a new species of insect to photograph every day he took out his camera. More than a dozen years since beginning, Brian’s still finding new species; he has identified 400 and has a huge backlog of photos yet to key out. What has appeared through his photography is a seasonal progression of brilliantly colored organisms that interact with the plants and each other, while also feeding birds and other creatures up the food chain. What others commonly dismiss as pests have, for Brian, become one of his garden’s most intriguing elements.
I haven’t uncovered a blueprint. The gardens this rethinking could lead to are sure to be as diverse as the gardeners who create them. The important thing is making a start.
Goldfinch image: Jongsun Lee/Unsplash