SILVER SPRING - Old-fashioned weed whackers of the four-legged kind are at work in one overgrown corner of Montgomery County.
Fifteen goats have been put on the payroll, charged with doing what two-legged creatures and truckloads of chemicals have failed to do: control the spread of weeds and vines, brought long ago from other countries, that are choking trees and other plants throughout Maryland.
They do it by doing what goats do best - eating, a lot.
"Anything is worth trying," said Sally Gagne, founder of the Friends of Sligo Creek, a nonprofit environmental group.
Non-native invasive plant species, as they are called, are a problem in Maryland and throughout the country.
Environmentalists consider these foreign invaders the No. 2 threat to biodiversity, second only to the loss of habitat that comes with suburban sprawl.
To slow the plants' expansion in the park, Montgomery County has tried everything. Teams of volunteers the weeds out of county parks. Staff members mow down fast-growing fields. They have used herbicide to target the nastiest of the vegetation.
Still, it grows.
"You know what snakehead fish are to the water? These plants are that to the parks," said Nancy Lineman, a spokeswoman for the Maryland-National Capital Park and Planning Commission.
So they brought in the goats this week as an experiment.
This is the first time goats have been used to attack this problem in a public park in Maryland, officials said.
But goats have long been used in the West to get rid of unwanted foliage. In California and Arizona, they have been used to clear out brush that feeds forest fires. North Carolina just started using them as an alternative to spraying.
Wild roses and vines
Officials here are specifically interested in getting rid of the multiflora rose, which takes over and dominates meadows, and porcelainberry, which eventually covers trees and kills them. Both were brought to the United States from Asia, where the food chain keeps their growth in check as they are devoured by animals native to that continent.
"Most of [the non-native plants] were brought here on purpose because people thought it would be good in their gardens or their farms," said Geoffrey Mason, senior natural resources specialist with the Maryland-National Capital Park and Planning Commission. "Multiflora rose was promoted by the USDA."
The goats being trucked to the Sligo Creek park each morning this week belong to Brian Schiner, owner of Wagon Wheel Farm in Mount Airy.
He's being paid $2,000, grant money from the Department of Natural Resources and the Metropolitan Washington Council of Governments.
Money aside, the goats need the work. Schiner raises his South African goats for meat - and he says he is always looking for a free lunch for his herd. He said he used about 80 of them when he built his house in the woods of Howard County, sending them out for a week, 24 hours a day to clear the 2-acre plot.
A farmer nearby uses Schiner's goats to mow a wet spot on his land where he can't take his tractor. They've helped clear lots for buildings.
His bucks are famished. They've just come off breeding season and each lost 30 pounds or so chasing does around the pen.
They're being given only water at night to be sure they are nice and hungry from 7 a.m. until 3 p.m. while they're on eating duty. Otherwise, they'd certainly be asleep on the job under a shade tree.
The goats have been set loose on a quarter-acre chunk of the park, an area cordoned off with a portable electric fence along a busy stretch of Forest Glen Road not far from Holy Cross Hospital.
They were chomping away yesterday at what, to them, likely looked like a giant salad. At times standing on hind legs to reach the higher leaves, they made quite a dent by midmorning.
Mason and others will study how much the goats eat, which plants they seem to prefer and whether they're meeting their goal of actually killing the pesky weeds - or at least slowing the rapid march across gardens and parks.
Officials need to find out whether the animals have pulled out the roots or just made a superficial change by chewing the vines bare.
Should the pilot program be deemed a success, the parks agency would look into acquiring a herd of its own.
"It has a lot of promise," John Galli, an environmental engineer with the Metropolitan Washington Council of Governments, said of the goat program.
The downside with goats, though, is the same as the upside: They eat everything.
The goats could potentially do damage if left in one area too long. They could gnaw the very native plants that people are trying to protect. And if all the food was gone, they'd certainly scale even an electric fence to get something more to eat.
Poison ivy for lunch
"If you put them where poison ivy is, they'd eat that," said Schiner, the goat farmer. "If there's nothing but pine trees, they'd eat them. If they ate a tin can, they'd be dead in the morning."
Those undiscriminating palates are just what worries Gagne.
"The huge question is how to get around the problem of eating the native plants," she said. "Still in all, this keeps them in check for now. ...
"If we don't do anything, in 10 or 20 years, it'll be too late. We'll be so overrun that we'll have nothing to save."