If you’re driving in Hyattsville near the Anacostia River and come across a tribe of goats, don’t bother them: They’re working. For the second time, the Anacostia Watershed Society has recruited 60 goats to eat an invasive plant along the northwest branch of the river.

The kudzu plant, native to East Asia, can grow up to a foot a day, according to Ashley Parker, the restoration project manager for the Anacostia Watershed Society, and prevents native plants that keep runoff out of the river from actually growing. The plant is not poisonous to the goats.

Anacostia Watershed Society is renting the goats for a full week—-May 9 to May 15—-from the company Eco-Goats for $7,000. (That’s about $117 per goat.)

“It will hopefully improve water quality, so the natural plants can capture rain run-off,” Parker says.

The goats will be fenced in, and there will be a security guard present at night to thwart any potential goat theft. Parker says no one tried to steal the goats when the Anacostia Watershed Society used them last fall, but there was a drunk driving incident in which someone drove a car through the fences. (No goats were injured.)

The kudzu plant has been used for centuries to make tea, health tonics, and fibers for kimonos, according to Smithsonian magazine.  The plant was first introduced in the United States as an ornamental vine shading a Japanese pavilion during the 1876 Centennial Exposition in Philadelphia.