Minnetonka is the latest city to enlist goats to clear invasive plants in parks

A herd of goats is blissfully living in Purgatory. That is, in Minnetonka.

The 22 goats are feasting away this summer on buckthorn and garlic mustard at Purgatory Park, part of the west metro suburb's experiment to see if the voracious creatures can help combat the spread of invasive species.

Minnetonka is the latest metro-area jurisdiction to try using animals to tackle the problem in an eco-friendly, nonchemical way.

Mendota Heights deployed sheep last month, courtesy of the nonprofit Great River Greening, to clear city property after having previously used goats and horses. The Three Rivers Park District has used goats and pigs to rid a Minnetrista farm of invasive plants, and Minneapolis plans to test out goats this fall.

But Minnetonka is stationing the goats in its largest public park, near where dogs and pedestrians typically roam.

"I had some concerns about goats in a suburban area, but just seeing what they could do … it's another opportunity," said Jo Colleran, Minnetonka's natural resources manager. "People love the goats."

The city launched the experiment in early May, setting up the animals in a half-acre area with a solar-powered electric fence to keep the goats in and dogs and coyotes out.

The project, estimated to cost no more than $10,000, will continue through July.

Signs tell people not to feed or pet the goats — they're at work, after all, and not there for spectators. They munch away at the plants 24/7 at Purgatory, a 155-acre park given its ominous name by settlers who deemed the swampy area the worst trail they had traveled.

Now it's a lush green park with picturesque meadows and wooded trails. But while the park may look healthy, Colleran sees pesky proliferating plants like garlic mustard that have invaded the forest floors, crowding out native plants.

"It's just taken off like wildfire," Colleran said of garlic mustard. "This year it has just boomed."

Enter the goats. They're on overtime duty, feasting away on the invasives. On Friday, the brown-and-white goats quietly huddled in the rain under a tree canopy while chomping and chewing on the tall garlic mustard plants.

Goats are particularly effective for the task because enzymes in their saliva kill garlic mustard and buckthorn seeds, so they don't survive passage through the digestive system.

They also can get to hilly, hard-to-reach areas of the park that 300 volunteers who hand-pull invasive plants can't reach. And it's an eco-friendly way to restore the land.

"Sometimes people feel like we're having a losing battle [with invasive species], but … you see results," said Jake Langeslag, owner of the Faribault company, Goat Dispatch, that owns the goats.

Even goats have their limits, however. Either they will have to come back again and again to kill off re-sprouting plants, or Minnetonka will have to use chemical treatments.

"Goats eat plants; that doesn't necessarily kill plants," said Angela Gupta, a University of Minnesota Extension educator who focuses on invasive species.

Research still needs to be done to find out how effective goats are in managing invasive plants, the health effects on the animals and the economic impacts, she said. But it's clear that more places in Minnesota are turning to goats.

"Goat management of invasive species is more common," she said. "Everybody likes to see goats; they are usually perceived better than herbicide applications. … It's just one more tool in the toolbox for invasives."

Colleran said the experiment will reduce the need for chemicals to kill invasive plants in Minnetonka. After moving the goats to another park at the end of the month, the city will wrap up the project at the end of July and determine how the goats did.

"We have no quick fixes for invasive species," said Janet Van Sloun, the city's natural resources specialist. "We can make a difference if we work on a specific area and we come back for numerous years. You'll hopefully get it down to a manageable level."

Kelly Smith • 612-673-4141