Initiatives such as the Million Pollinator Garden Challenge are spurring the movement to repair damaged ecosystems, one garden at a time.
Healthy habitats support complex systems of life: a diverse menagerie of insects, birds and other beasts living among a tapestry of native plants in layers of branch, leaf and flower. Both local and migratory wildlife require these healthy ecosystems for food, water, shelter, nesting sites and places to rear their young.
Ideally, interconnected native habitats guide birds and certain butterflies along north/south migratory flyways from safe winter sites to breeding-friendly spring locations. But our native habitats, and the lives that depend on them, need help.
“Progress” in the form of human encroachment has eliminated, chopped up and degraded native habitats, which have been paved over and poisoned, replaced by roads, malls and lawns, and invaded by non-native plants.
And now, the destructive impact on these natural systems has reached a crisis.
University of Delaware entomologist Doug Tallamy alerted the public about threats to healthy habitats and natural ecosystems in his award-winning book Bringing Nature Home (Updated and Expanded) (2009, Timber Press).
“We humans have taken 95 percent of nature and made it unnatural,” Tallamy said. And, since “species are lost at the same proportion with which a habitat is reduced in size,” we need to turn things around or risk massive extinctions.
It’s not too late to save habitat by bringing it into our gardens, though.
Tallamy has introduced gardeners to a solution, a way to rebuild and reconnect natural systems.
He encourages gardeners to consider their landscapes as wildlife preserves, as perhaps “the last chance we have for sustaining plants and animals that were once common throughout the U.S.
“If we start sharing our landscapes with other living things, we should be able to save much of the biodiversity that still exists,” Tallamy said.
Gardeners across the nation are now taking on the challenge of rebuilding habitat and supporting biodiversity by choosing plants and using sustainable management methods.
“Even modest increases in the native plant cover on suburban properties significantly increases the number and species of breeding birds, including birds of conservation concern,” Tallamy said.
Native plants support life cycles
Daniel Bish is the owner of Plant Oregon, a native plant nursery, restoration and landscaping operation in southern Oregon. He encourages “less formal, more congested, wilder landscapes” because they provide better habitat for insects, small mammals and amphibians that depend on each other in the cycles of life.
“If we pull blocks out of the ecological tower,” Bish warned, “it will be susceptible to collapse.” But a well-tuned system demonstrates “the rhythmic timing of native flowering plants and the rhythm of wildlife cycles.”
For instance, migratory hummingbirds time their spring arrival in the state to take advantage of early blooming Ribes sanguineum (red-flowering currant), an important nectar source.
Bish promotes honoring our natural heritage by reintroducing elements of it, too.
“We live in one of the most beautiful regions of the world with an amazing diversity of plants,” he said. “Is it not respectful to encourage its recovery into the spaces it once occupied? Imagine the diversity of life that once flourished here. It only seems right to give the small spaces that are left the dignity of ancestral vegetative cover.”
Sarah Elvington, nursery assistant at Plant Oregon, explained the value of building habitat: “By planting native species, we bring ourselves closer to the network of life around us, and we receive insights into a world unnoticed by many.
“Gardeners can help sustain natural ecosystems while contributing to future biodiversity by carefully choosing plants and grouping them in plant communities. Cultivating native plants increases our connection to place by deepening our awareness of water conservation, nutrient cycles, identification of invasive plants, and preservation of native species.”
Rebuilding native habitats
“Nurture nature with native plants” is the motto of Esther Gruber McEvoy, owner of Willamette Gardens, a retail and wholesale native plants nursery in Corvallis, Oregon.
Native habitats are unique and specific to sites, McEvoy said. Whether rock garden, moist or wet woodland, marshland, dry or wet prairie environment, habitats vary by the amount of available water and sunlight, type of soils, and exposure to the elements. Habitat gardening uses site-specific plants to create site-appropriate habitats, she said.
“One can build habitat gardens without using native plants exclusively,” McEvoy said. “Yet, by using local native plants you are helping the local wildlife that is adapted to the local vegetation for completing their life cycles and for their future generations.”
McEvoy has seen the results of using native plants at her own nursery.
“Flocks of cedar waxwings come eat the seeds of the native hawthorns and the madrone in the fall. Flocks of bushtits eat aphids from lupines and roses. Red columbine and red-flowering currants are great nectar sources for hummingbirds. Leaving leaves and not deadheading native plants are ways to provide great habitat for overwintering insects and food for wildlife too,” she wrote.
Replacing arborvitae hedges with native evergreen plants can be a challenge, but hedging with a combination of native deciduous and evergreen shrubs creates a winning combination with a variety of berries, flowers and habitat.
She recommends several evergreen shrubs for hedging, including tall Oregon grape (Mahonia aquifolium), blueblossom (Ceanothus thyrsiflorus), wax myrtle (Myrica californica) and silktassel (Garrya elliptica) for areas without heavy snowloads. Coyote brush (Baccharis pilularis) survives tough winters well for sunny sites, and for shady sites, McEvoy recommends salal and evergreen huckleberry.
Good native deciduous shrubs for mixed hedges include Spiraea douglasii, snowberry, red osier dogwood and mock orange (Philadelphus lewisii).
Naturescaping for habitat
Habitat gardening is naturescaping, said designer Amy Whitworth of Plan-it Earth Design in Portland, Oregon.
Whitworth works closely with the Backyard Habitat Certification Program, a local collaboration between Audubon Society of Portland and Columbia Land Trust (www.backyardhabitats.org).
Her customers want to support wildlife, biodiversity and healthy ecosystems and seek her out for those reasons.
What is involved?
“Removing invasive plants, adding native plants, gardening without chemicals, using the principles of forest layers, retaining fallen leaves and organic matter, keeping stormwater on site when possible, and boosting soil biology” all contribute to the concept of habitat gardening, Whitworth said.
“It’s not so much individual plants as it is the community and the layers of canopy from the ground plane to the upper reaches of the tallest trees and how those layers provide pathways to food, shelter, water and nesting,” she explained.
Ribes sanguineum not only provides nectar for hummingbirds, Whitworth said, but also fruit for other birds and a certain amount of cover. Although it is somewhat large for urban gardens, it is “worth working around” for its high value to wildlife.
Indian plum, which blooms earlier than Ribes, is another important nectar source for hummingbirds. Ninebark and elderberry are good for butterflies and are host plants for their caterpillar larvae. “Birds eat the caterpillars, so everyone wins,” she said. Serviceberries are a favorite food for cedar waxwings.
The beautiful Trillium kurabayashi with red flowers and spotted leaves, a native to southern Oregon, has a unique relationship with smaller critters, Whitworth said. Ants move the seed around and plant it by eating the fleshy covering and bringing the seed into their nests, she explained.
Soil biology — the relationship between plants and the soil community — can contribute to or impede success, Whitworth said. Since some common natives like salal, evergreen huckleberry and Oregon grape can be hard to establish, Whitworth recommends inoculating the soil with a handful of soil from an area where the plants thrive. Doing so introduces helpful microbial elements and seems to help plants get established and thrive, Whitworth said, although she qualifies this recommendation as being “entirely anecdotal.”
Reclaiming the ravine
Habitat gardening is about sharing our spaces with nature, according to sustainable landscape designer Vanessa Gardner Nagel, APLD of Seasons Garden Design in Vancouver, Washington.
“It is creating a garden that works for native plants and animals, while still being a garden for us to enjoy,” she said. “Gardens should be shared experiences, keeping out invasive plants and encouraging natives that work well in the specific environment.
“If we get away from the overly demanding sort of gardens we’ve had in the past and approach gardening like nature does, in layers of plants that work in the environment, we can still serve nature and our personal aesthetics at the same time,” she said.
Reclaiming a steep ravine on her property involves removing the smothering blanket of invasive English ivy. Without the use of chemical herbicides in the sensitive native environment, Nagel has developed a routine of “pulling and using a mattock to get underneath enough of it to roll it back, then cut it off.”
She wants to replace the invasive plants with at least two-thirds native plants while also making it an interesting garden. In especially steep areas, she relies on ferns and grasses with root systems that minimize erosion. She plans to introduce native salal, which isn’t currently there, to join the snowberry, Indian plum, bigleaf maples, skunk cabbage, trillium and Douglas firs that occupy the ravine.
Nagel is adding evergreen huckleberry plants and seedlings of Oregon grape, too. Limiting selections to white-flowered natives is one way to whittle down the options, Nagel said, and textural combinations like goat’s beard and white foxglove increase interest. Extremely drought-tolerant Philadelphus lewisii will work well on the south-facing section, and ephemerals like columbine will lend spring interest.
“Everything contributes to creating a natural environment that serves the bugs, the bees and other critters like salamanders and frogs,” she said.
Even though not everyone can tackle the challenge of large-scale native renovation, including some natives in every garden will create links to larger areas of native habitat and eliminate so-called ecosystem deserts one yard at a time.
Gardeners in every part of the country can help rebuild habitat, and location-specific resources help gardeners introduce appropriate native plants.
National Wildlife Federation, the largest private, nonprofit conservation education and advocacy organization in the U.S., provides educational resources and certifies wildlife habitat in gardens, communities and schoolyards.
A new tool with recommendations for the best native plants for wildlife by zip code has recently launched on the NWF website. A joint effort by Doug Tallamy, the National Wildlife Federation and the U.S. Forest Service, it is a work in progress based on Tallamy’s research into which plants host the largest numbers of moth and butterfly caterpillars.
The Million Pollinator Garden Challenge is an effort to mobilize America’s gardening community to add more native, non-invasive pollen and nectar-producing plants to reverse declining pollinator populations.