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STEVENSVILLE - A new cash crop has arrived in this historic agricultural community, long the home of cattle ranches and hayfields.

Nate Lengacher is growing roofs.

Called "green" or "living," these house-toppers are made of sedum and other region-specific succulents that begin life as seeds in a field, then are carefully watered and weeded until they're robust enough for an elevated life.

Tucked between horse pastures off Ambrose Creek Road is Lengacher's hope for a more sustainable and green future for America's homes and buildings.

"This system is simple and straightforward," Lengacher said of the mix of sedum and drought-resistant succulents he is growing on an acre of leased land. Not only is a green roof self-sustaining, he explained, it outlives traditional roofs by 40 or more years, and because of its longevity, it reduces landfill waste.

"As a roof, it has so many benefits: It's beautiful to look at, it provides bird and insect habitat, and it reduces urban island-heat effect," he said. "Cities tend to be 10 to 20 degrees hotter than surrounding areas - and if you have a building with a living roof, it reflects heat. These roofs are also great with managing stormwater runoff because they suck up the water and gradually release it."

By day, Lengacher works full time for Missoula County as a sanitarian in the environmental health department, but in the early mornings and late evenings, he tends his unusual crop.

Last week, he and his friends harvested the plants for a home in Salt Lake City. Harvesting takes on a slightly different meaning in this context, for the material grows on specially designed mats that are rolled up like sod and are moved and installed in the same way.

Next week, most of his crop will be rolled up and hauled to Washington state where it will be used to cover the Nintendo Co.'s new building in Redmond.

The green product is officially called Xero Flor, after a 30-year-old system designed in Germany and modified for North American climates, said Clay Rugh, general manager for Xero Flor in North America.

Rugh, a former Michigan State University professor of environmental biotechnology, founded the company's North American branch in 2002 after learning about the product while researching alternative energy and soil remediation.

Headquartered in North Carolina, the company has installed more than

1.2 million square feet of green roofs in North America. Xero Flor currently has more than 35 acres in production in various regions across the country, with each region cultivating plants suited for its climate.

Lengacher's Stevensville farm, which launched this summer, is the company's only production field in the Rocky Mountains.

As America becomes more educated about alternative building materials, more people are becoming familiar with living roofs, Rugh said.

"The education baseline has moved up a little bit since the time I started this," he said. "It used to be that 99 out of 100 calls completely stumped people, and I think now 75 (percent) to 95 percent of the people in the design/building community know what green roofs are."

Once people know the basics, green roofs are easy to sell because they make sense, Rugh said.

The chief selling point is the extension of a roof's lifespan.

"Traditional roofs and waterproofing systems last maybe 10 to 12 years, but a green roof lasts 40, 50, even 70 years before it needs to be replaced," he said.

Although the concept is new in America, in Europe green roofs have been around a long time and have long proved their merit, Rugh said.

"You open up a telephone book in Germany and there are full pages of green roof businesses and providers," he said. "The technology has been well tested and proven."

Installing a roof is no more or less difficult than any other roofing project.

Xero Flor unrolls the plant material like sod. It takes some initial watering to get the roof acclimated to its new home, but then it becomes worry-free.

"A roof is intended to be self-sustaining as much as possible, and be low maintenance - that's the point," Rugh said. "Our system is especially designed with that in mind. We don't want it to be a burden."

Cost varies depending on the type of building and pitch of the roof.

Generally, a lightweight green roof that would be suitable from most houses costs on average about $10 per square foot.

To ensure that the roof does its worry-free job for decades, the company is involved from the very beginning with the design and roof installation, Rugh said.

Missoula homeowner Pat Supplee has the only Xero Flor living roof in Montana, which she had installed in 2007.

The O'Brien Creek home was featured in a green home tour of Missoula that year, and that's where Lengacher first saw a living roof and became fascinated by the Xero Flor product.

Supplee said her enthusiasm for her unusual roof hasn't waned from the first day it went in - it's only deepened over time.

"I love it," said Supplee, a Missoula architect who owns Studio Modera. "I'm such a fan because there is no maintenance and I don't have to weed it.

"The roof seeds itself, and I'm not a green thumb and the roof is flourishing."

Having lived with a green roof for two full seasons, Supplee said she's come to appreciate other side benefits.

In the summer, the once-blistering roof now makes for a cool oasis to escape to; in the winter, the plants keep snow on the roof longer, making for an additional layer of insulation that allows her to keep the home warmer - without a big heating bill.

"And I love that it changes with the seasons," Supplee said. "We have 11 different varieties of sedum, and depending on the time of the season we have different flowers that bloom. Right now we have yellow flowers, and in the fall it gets these nice ruddy fall oranges and red colors.

"It's just wonderful all year long."

Reporter Betsy Cohen can be reached at (406) 523-5253 or at

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