Green collar workers
The Window Box Gets Some Tough Competition
In this place where the political climate, too, is green, it is perhaps not surprising to encounter a hardy new perennial in the world of horticulture — the green roof gardener.
While others nearby toil over grapes and artichokes, Cooper Scollan spends his days hunched over some 1.7 million baby sedum and other native plants destined for hillocks atop the green roof at the new California Academy of Sciences building, nearing completion in Golden Gate Park.
Mr. Scollan, 30, is a green collar worker, responsible for the safety and well-being of what soon will be the largest continuous swatch of vegetation in San Francisco. The academy, designed by the architect Renzo Piano, whom Mr. Scollan has seen only on television, will feature the country’s most technically ambitious eco-roof, the latest example of what is known in highbrow circles as “regenerative” or “living” architecture.
It is a growing movement that originated in Germany and now includes, to name a few, bottlebrush grasses and wild rye atop Chicago City Hall, succulents on the 10-acre roof of Ford’s River Rouge truck plant in Dearborn, Mich., flowering chives and dianthus on the Bronx County building in New York, and, at an office building for the Gap in San Bruno, Calif., a coastal oak savannah landscape.
Though green roofs are hardly new — think of the fabled hanging gardens of Babylon — eco-roofs may represent gardening’s next frontier, as cities from Los Angeles to Chicago offer incentives, including fast-tracking development, to builders who forgo drab stretches of concrete in favor of a living roof. The reasons are pure Al Gore: the new California Academy of Sciences roof is expected to reduce storm water run-off by half. That water will then be used, instead of potable water, to flush toilets.
The design is also calculated to prevent the release of more than 405,000 pounds of greenhouse gases and substantially reduce the urban “heat island” generated by roads, sidewalks and parking lots.
More poetically for Mr. Scollan, who is fond of comparing his favorite plant, the towering blue “Pride of Tenerife,” to Marge Simpson’s hair, the poppies, strawberries, sedum and other California native plants on the roof will provide a wildlife park in the sky protected from windblown weeds and the vagaries of man. Should all go well, it will also attract the endangered San Bruno elfin butterfly, a coppery brown temptress.
Like meditation, he said, gardening is repetitive yet constantly changing. “Plants, like insects, metamorphize,” he philosophized, “transforming from a tangled mass of cells into a fig hanging in midair.”
As nursery manager for Rana Creek Habitat Restoration, an ecological design firm, Mr. Scollan is one of a growing number of green roof gardeners. According to a survey last year by Green Roofs for Healthy Cities, a nonprofit industry association based in Toronto, over 3 million square feet of green roofs were planted in North America in 2005, worth about $60 to $80 million. This year growth is expected to rise 125 percent, between 6 and 7 million square feet, said Steven Peck, the group’s founder.
Gardeners like Mr. Scollan are tackling challenges at once similar and distinct from “terrestrial” gardening, in the words of Ed Snodgrass, a pioneering green roof nurseryman in Maryland who writes an “Ask Ed” column for green roofs.com and is the author of the definitive “Green Roof Plants: A Resource and Planting Guide” (Timber Press, 2006).
Mr. Scollan checks his brood each morning, when this stunningly pristine valley is still swaddled in mist. The plants’ environmental pedigree does not fend off nature’s whims: Mr. Scollan buys copious amounts of chunky peanut butter to put in mousetraps — 20 traps a week — to discourage mice from dining on mosses or on the prunella, a plant with tubular purple flowers beloved by hummingbirds.
Mr. Scollan personally raised the prunella from seed, hand-collected in Point Reyes, starting with a couple of hundred that, in less than a year, have generated more than 200,000 plants.
Although his enemies are typical — mites and aphids are high on the hit list — the unusual configuration of the roof has required horticultural derring-do. Mr. Piano’s third-story design resembles the downhill ski run at the Winter Olympics: it includes seven steep undulating hills. (Mr. Piano, who designed the new building for The New York Times, created his first green roof for a project in Berlin.)
Plants will adhere to the daunting slopes by way of 50,000 “bio trays,” biodegradable planters made from coconut fibers that allow roots to attach the trays to one another and also to the soil. (A waterproof membrane and fabric mats protect the roof from water.). As on all large green roofs, the soil is not dirt exactly but a gravel-like growing medium of granulated pumice, shales, clays and other minerals.
Paul Kephart, the founder of Rana Creek, calls the roof “the most challenging vegetative structure in the world.” The need for gardening ingenuity is likely to increase as green architecture gets ever more sophisticated, Mr. Kephart said. “The cultural idea of a beautiful place now includes ecology, aligning nature’s life cycles to ours,” he said.
Although less prone to weeds than earthbound gardens, green roofs tend to be drier and windier, said Mr. Snodgrass, a fifth-generation alfalfa farmer who saw a market niche and established one of the country’s first green roof nurseries. The logistics of roof gardening — in the case of the California Academy of Sciences, 2.6 million pounds of plants and soil — require immense forethought, especially the issue of weed-hauling.
“You do need to think about how you will get everything on and off the roof,” said Mr. Snodgrass. “It’s a whole different world than pulling up to the sidewalk in a pickup truck.”
Daydreaming while gardening is not a good strategy. “You have to be mindful that there’s an edge,” he said.
If drought-tolerant green roof grasses and other plants are a new American crop, pioneers like Mr. Scollan, who carries a pruner, assorted plastic frogs and a beat-up copy of Scientific American in his Honda, are brave new harvesters. His passion for plants started early: his mother has a green thumb. He first studied ornithology, including a stint in Central and South America with Roger Tory Peterson, who, he recalled, “could hear an Eastern meadowlark a quarter mile away with the radio on.”
Green architecture may one day be the equivalent of medieval cathedrals, but with living things the architectural inspiration, rather than soaring stone and glass.
For Mr. Scollan, creating life for the tops of buildings is “Jack and the Beanstalk” redux, but with an eco-twist. “Plants are the true magicians,” he said. “With just a few seeds sown, a whole new world is grown in the sky.”