Going Native: Biodiversity in Our Own BackyardsTop designers show how to combine exquisite wildflowers and other native species in spectacular plantings that provide a refuge for beleaguered plants and animals. Features scores of spectacular native plants and garden plans for every region.
- What is a Biodiverse Garden?, by Janet Marinelli
- Biodiversity State by State
- Natural Landscaping Basics, by Jane Scott
- Biodiversity in the Barrens: A Biodiverse Garden for the Pine Barrens, by Karen Blumer
- A Taste of the American Subtropics: A Biodiverse Garden for South Florida, by Georgia Tasker
- A Joint Venture With Nature: A Biodiverse Garden for the Midwest, by Neil Diboll
- Where Neatnicks Need Not Fear to Tread: A Biodiverse Garden for the City, by C. Colston Burrell
- Stranger in a Strange Landscape? A Biodiverse Garden for Dallas, by Sally Wasowski
- A Low-care Natural Landscape: A Biodiverse Garden for Colorado, by Gayle Weinstein
- Biodiversity in the Desert: A Biodiverse Garden for Arizona, by Carol Shuler
- A Garden that Redefines Our Role in Nature: A Biodiverse Garden for the California Foothills, by Ron Lutsko, Jr. & Robyn S. Menigoz
- Making Nature a Part of Daily Life: A Biodiverse Garden for the Pacific Northwest, by Andy Rice
What Is a Biodiverse Garden?
by Janet Marinelli
I grew up on Long Island on a block called Garden Place. Sounds like a perfect name for a horticultural soap opera. Ecologically, it could have been scripted by Stephen King. Grandma grew tomatoes. Dad mowed the lawn. Every Mother's Day Mom got another pink azalea or the latest shade of creeping phlox. Today, my childhood home looks like just about every other suburban garden from Boston to Seattle, with its golf course-quality lawn, clipped yews, azaleas and shade trees ringed by begonias.
When Henry Hudson landed on Long Island in 1609, he sang the praises of its white ocean strands carpeted with beach plum and prickly pear. As more and more families like mine settled on Long Island, I watched the beach plum get trampled. Much of the ancient oak forest that blanketed the island's spine yielded to suburban sprawl. The Hempstead plains, once the largest prairie on the East Coast, today is virtually extinct; also extinct is the Eskimo curlew, a beautiful bird with a long, curved bill, which was once hunted there. But I never put two and two together. Only in the past few years have I realized what ecological devastation conventional gardening has wrought.
We are poised on the brink of an age of extinction, a disaster to rival anything in evolutionary history, including the mass extinction of the dinosaurs 65 million years ago. As wilderness shrinks and backyard acreage increases, the home gardener's role in this biological debacle grows ever greater. Across a continent of breathtaking diversity we've planted the same two or three dozen plants. No wonder botanists are concerned about the long-term survival of almost 4,300, about 20 percent, of this country's native species—plants that are critical habitat for countless other creatures.
Our gardens threaten biodiversity in other ways as well. Free of the checks and balances that controlled their numbers in their original lands, scores of imported plants have jumped the garden gate and swamped our native vegetation. Park and preserve managers struggle daily to control these invasive pests.
The U.S. Census Bureau calculates that the nation's suburbs have almost doubled in area in the past two decades, and 400 square miles are added every year. As suburbia encroaches on natural areas, there is less room for plants and animals. During the 1960s, scientists first recognized that smaller areas also hold fewer kinds of plants and animals. According to their best estimates, a tenfold decrease in area slashes species diversity in half.
As garden acreage increases, natural areas are not only growing smaller, but also more isolated from each other. Habitat fragmentation threatens genetic diversity, another basic level of the diversity of life. When populations of a species are cut off from one another, they are unable to exchange genetic material and inbreeding occurs. One likely result is that future generations will be less able to adapt to changing conditions, whether possible global warming or an imported insect pest. Because genetic variation is the material from which new species evolve, another probable result is less biodiversity over the long haul.
Gardens have a much more immediate effect on genetic diversity. Many of the plants at nurseries are named cultivars, which are propagated asexually, usually from cuttings (not sexually, from seed), as that's the only way to preserve the characteristics of the parent plants, whether a compact growth habit or a certain color leaf. So when you buy, say, Aster novae-angliae 'Purple Dome', a compact, mounded cultivar of New England aster, you are buying a clone—a plant that is genetically identical to every other specimen of 'Fancy Fronds' in existence.
A Garden that Acts Like Nature
The goal of conventional gardening is to create an idyllic picture, a place where plants bloom prodigiously amidst expanses of perpetually green lawn. We urge our little patches of paradise to grow, grow, grow and bloom, bloom, bloom with continuous infusions of fertilizer and water. Then, with puritanical zeal, we thwart their sex drives by mowing and deadheading, lest seed from a single plant scatter promiscuously across the land.
Granted, ever since the 18th century when tastemakers began to rail against formal landscapes in which virtually anything green was sheared into lollypops, poodles and peacocks, western gardens have become increasingly natural looking. English designers created a new landscape ideal of trees and grass—which suburban gardeners here have devotedly adopted. But it's no longer good enough to create gardens that look like nature. As the poet Frederick Turner has pointed out, we must create gardens that act like nature, that do what nature does. What nature does is reproduce itself, copy itself into the future, gradually improving on the copies by the evolutionary forces of sexual reproduction, mutation and selection. In order to act like nature, a garden must consist of plants that are suited to the conditions on the site and can thrive with minimal intervention by us. (However, they must not be invasive thugs.) One of the best things about most biodiverse gardens is that, once established, they require little maintenance. Our job as gardeners is to combine plants in "communities" that enable them to form the sorts of mutually beneficial relationships with other plants and animals that allow them to prosper and reproduce. Then we should let a thousand seedheads shatter, confident that our horticultural creations will add over time to the exquisite forms of life that comprise biodiversity.
Because centuries of gardening the old way have made it hard for us to visualize the new ecological gardens, I asked some of this country's top native landscape designers to create a sample garden for the typical piece of property in their regions, complete with a landscape plan. From a biodiverse garden for the Long Island pine barrens to one for the California foothills, these landscapes include a diversity of species in a variety of habitats. They perform the vital task of re-creating the rich ecology of native plant communities that are disappearing from our land and our lives.
By now you're probably thinking that I've gone bonkers. What has the world come to when you can't even plant a perennial border without being politically incorrect? A few proponents of native landscaping are indeed biological extremists who consider all humans ecological outlaws and planting exotics a form of environmental treason. Hogwash. In the biodiverse garden, humans are a part of nature, not apart from it. A biodiverse garden includes plantings that celebrate our own species' long and fruitful relationship with the land, from elegant herb gardens accented with topiary spirals to patios edged with fragrant flower borders. And there's certainly room in our gardens for healthy, home-grown food. But these traditional plantings belong close to the house, and our natural habitat gardens toward the edges of our properties.
Someday we'll know enough about ecology to be able to create new plant communities combining species from around the globe that add to, rather than subtract from, Earth's wonderful diversity of life forms. We don't know how to do that yet. Our current system of scattered nature preserves in a larger suburban landscape is not working as a biological safety net. Chances are slim that much more American land will be cordoned off as wilderness to provide threatened species with ample living space. That means we gardeners have an important role to play in efforts to re-create the native habitats we have been destroying.
Imagine the possibilities: a new landscape in which biodiverse gardens link up to form a network of corridors that crisscross the continent, connecting nature preserves so that animals can move freely and plant seeds can disperse. Planting these gardens can be our great gift to the planet.