Even though just 50 homeowners are participating so far (and only 17 homeowners have earned signs), the ultimate goal is to prevent the spread of the most aggressive weeds from the targeted area in the West Willamette Corridor by 2019. And by partnering with the Audubon Society, Cronlund intends to take the Backyard Habitat Certification Program citywide next year. By 2012, she hopes to have a thousand homeowners participating.
The idea that a private homeowner might be ethically responsible for what he chooses to plant in his yard is a relatively new one. Bringing Nature Home author Tallamy, who also chairs the department of entomology and wildlife ecology at the University of Delaware, says that the days of “purely ornamental” gardening are over, and argues that a slow cultural shift is taking place in what Americans consider beautiful in their yards.
Tallamy, a frequent visitor to Portland (his son lives here), says the city is in a unique position to set an example for the rest of the country—some 56 percent of which is now developed with suburbs, cities, and four million miles of roads and highways. “Because Portland has Forest Park, it’s better off than most cities,” he tells me. “But you’re still in danger. You can’t ignore the reality that 73 percent of Portland’s original forested areas have been cut down.” Because public parks encompass only about 13 percent of Portland’s landscape, Tallamy argues that private-property owners can make the most immediate, large-scale impact in restoring native habitat.
“It’s not just a matter of telling people what to do as telling them how their plants function in the ecosystem,” says Tallamy. “It’s often amazing to me how many people don’t really know what’s growing in their yards.”
State officials, too, are sounding the alarm on backyard invasives. The Oregon Department of Agriculture estimates that 21 of the 114 plants on its “noxious weed list” cost Oregonians at least $83 million a year in lost revenue and production. An economic study completed in 2000 by the department even determined that a single plant, Scotch broom, was soaking the state for $47 million a year, because it outcompeted trees and subsequently lowered timber production. Like many such aggressive weeds, this low, shrubby plant with tiny yellow flowers probably was first introduced as an ornamental before invading natural areas.
“The important message here is that invasive weeds do not respect ownership boundaries,” says Tim Butler, the manager of the state agriculture department’s noxious weed control program.
Natives aren’t always the most attractive, but you don’t have to give up the beautiful flowers entirely.
Ask mayor-elect Sam Adams who’s to blame for Portland’s problems with invasive species, and he’ll tell you that it’s not ?homeowners but the city itself. “It’s a mark of shame on city government,” says Adams, who has spent three years as the city’s environmental commissioner. Surveys conducted by the Portland Parks and Recreation Department in 2003 and 2004 rated nearly 23 percent of the city’s natural parklands as “poor” or “severely degraded”—problems officials attributed partly to nonnative plants, which were growing rampant on private land adjacent to the surveyed areas like Forest Park and which were overtaking these spaces. To raise awareness about Portland’s invasive species predicament, Adams has held “Ivy Summits” at City Hall. He’s spent weekends yanking the vine from parks, and has even appointed the city’s first “invasive species czar.”
“People just aren’t connecting the dots about invasives,” says Adams, noting that Portlanders continue to buy the plants at area nurseries. In fact, Adams wants to work with local nurseries and national chain retailers such as Home Depot to stop the sale of the most aggressive nonnative plants altogether. He even wants to institute a 10-year, citywide plan to remove these alien plants from private property. If residents don’t comply, says Adams, their properties could be ranked under the city’s “nuisance” classification, which is primarily reserved for abandoned buildings. “It’s all about establishing a timeline and penalties,” Adams says.
“Nobody in Oregon wants to be told what to do,” says Mark Sytsma, chair of Environmental Science and Management Programs at Portland State University and chair of the Oregon Invasive Species Council. “It’s going to take an overall shift in cultural mind-set. But if we can get people to really want native plants in their yards, we can adjust what they consider beautiful.”
Embracing native gardening does not, however, require people to embrace a wild forest aesthetic as Carole Kelly did. Consider Robin Jensen’s backyard, which is a manicured medley of vibrant flora, including native ferns, oxalis, and fringecup piggyback, as well as flowering nonnatives like fuchsia and dahlias. Koi nip at lily pads floating on the surface of a shallow pool; a stone path cuts through the modest lawn; and the flower bed adjacent to the house is full of heather, daylilies, and azaleas. It’s a good example of how a more orderly, landscaped garden can still be ecologically responsible: Beatty awarded Jensen’s idyllic garden, which cost over $25,000 to pull off, silver-level status last year (though Jensen has been planting a lot more natives in an effort to upgrade her status to gold.)