Most gardeners don't have a written habitat plan for their property, but Jo Roberts isn't like most gardeners. The shady ravine behind her house, with its trees, rushing creek and diversity of plants and birds, has become her work and her fascination. In a poem Roberts wrote to invite friends and neighbors to tour the garden a couple of years ago, she noted that she'd be showing the metamorphosis not only of Maple Creek but of Jo Roberts as well.

Such an understory garden may not seem unusual to many of us who grew up around Seattle. This kind of naturalistic, woodsy setting was commonplace in my neighborhood, taken for granted by kids and adults alike. We expected to see trillium poking up as the fern fronds uncurled, and it was not unusual to spot fat salmon swimming up the creeks to spawn. But many of these habitats have been destroyed in the past few decades as trees were cut down to make way for lawns and houses. Permeable ground and even creeks, diverted into culverts, have been paved over. In the remaining wooded areas invaders such as English ivy (particularly troublesome because of its shade tolerance) have choked out the native plants. These compromised areas are absent of birdsong and flower, the creeks strangled by runoff and debris.

Roberts is a Midwest transplant, and it took her nearly 10 years of living above such an uninviting space to understand what had happened and the possibilities for renewal. In her poem, she writes of her awakening, noting that the ivy was an "alien blanket" hiding rats and keeping birds from finding much of the food they needed to survive. It was clear, she declared, the vines must go.

Five years later, the last of 25 dumptruck loads of ivy was carted off the hillside. At the same time, Roberts had removed other non-native invasives such as bamboo, polyganum and wild morning glory. With nowhere to hide, the rats went, too. That first spring after the ivy-stripping was completed, native bleeding heart appeared all on its own.

"I was so dumb," exclaims Roberts, "when I came here I thought I'd let nature take its course." For years she had been involved in environmental activism on a larger scale, but it was only when she understood what the ivy was doing right beneath her that she became involved in saving the environment in her own backyard.

Perhaps most dramatic, and most appreciated by Roberts, is how a great variety of birds now flock to the site to feed, nest and shelter in the native plants. From her house and deck overlooking the ravine, Roberts has counted 38 species of birds, 15 of which nest on the property. Pileated woodpeckers make good use of the snags and stumps, red-tailed hawks and bald eagles hunt for prey. Roberts has even spotted barred and great-horned owls. Troupes of Eastern gray squirrels are joined by possums, raccoons and coyotes. And to think all this activity goes on behind a little house in the woods on a quiet residential street in Seattle's Maple Leaf neighborhood.

Most of the native plants didn't regenerate on their own. Roberts built a path with spaced timber steps down the hillside, and a boardwalk over the marsh. She coated the paths with hazelnut shells, their rich brown color blending with the surrounding woods. Roberts' planting has been largely experimental. "I put things in and then see if they come up," she says. "I try things two or three times and then they fight it out, they live or die."

Most of the plants she has put in, all natives, have not only lived but flourished. The marshy areas, fed by natural springs, are flush with the yellow flowers and fat, shiny leaves of skunk cabbage. Colonies of delicate white trillium light up the forest floor. A nurse stump, so hidden by ivy that Roberts didn't even suspect its existence, sprouts a hemlock sapling on one side and a huckleberry bush on the other. Wild ginger, oxalis, foam flower, piggyback plant, sword fern, salal and salmonberry now cover the slopes where the ivy once reigned. Deer fern, lady fern and Oregon grape, native strawberries and native roses soften the shady glens. To encourage maximum diversity of plant life, Roberts tries to maintain a 25 percent open canopy, not easy with the dozens of Douglas fir, red cedar, western hemlock, alder, big-leaf and vine maple hugging the hillside.

Now when Roberts walks the precipitous pathways down that hill to Maple Creek, something interesting is happening, underfoot or overhead, every day of the year. "You have to appreciate the delicate and the subtle," says Roberts of the native treasures that spring from the forest floor as if they've always grown there. To make sure the lively habitat will continue to flourish, she has established a Conservation Easement with the Cascade Land Conservancy, putting more than half of her one and a quarter acres into the easement. This agreement should protect her stretch of Maple Creek, and all the flora and fauna that inhabit it, well into the future.

For more information

• Cascade Land Conservancy is a private, nonprofit organization that works with landowners, organizations and governments to protect wetlands, shorelines, forests, wildlife and rare-plant habitats, stream corridors and urban open spaces. Phone: 206-292-5907. Web: www.cascadeland.org

• Washington Native Plant Society is dedicated to the preservation, conservation and study of our native plants. The Puget Sound chapter's annual native plant sale will be at the Bellevue Botanic Garden May 11, 10 a.m. to 4 p.m. Phone: 206-527-3210 or 1-888-288-8022. Web: www.wnps.org

Valerie Easton is manager at The Miller Horticultural Library. Her new book, "Plant Life: Growing a Garden in the Pacific Northwest" (Sasquatch Books, 2002) is an updated selection of her magazine columns. Her e-mail address is vjeaston@aol.com.