Grazing goats, fewer herbicides considered to fight weeds in Mpls. parks

The Minneapolis Park Board is considering two new tactics in the battle against weeds and invasive species — less pesticide in neighborhood parks and, where there's room to roam, goats.

A majority of commissioners favored those moves after getting an update this week on where and when park staff use herbicides, fungicides and insecticides plus a heavy dose of pressure to change course.

The proposed change to pesticide application in neighborhood parks would end the use of the compound glyphosate, the active ingredient in Roundup and half of the most commonly used herbicides in parks. But the most attention-getting directive is looking into the use of goats to graze back invasive species in two areas of the park system, a technique that's been used previously by Three Rivers Park District.

"I very much appreciate the passion and commitment of the many who showed up last night to voice their concerns about the use of this herbicide in our parks," Commissioner John Erwin said in a Facebook post this week. Erwin, a University of Minnesota professor and floricultural and horticultural specialist with U Extension, proposed the changes. "Roundup has been considered safe in the past, however, recent research raises some concerns as to whether this is true."

The plans were termed a "small victory" by one leader among several dozen anti-pesticide activists who packed Wednesday's board meeting to press for a ban. But Russ Henry, a potential Park Board candidate, said the activists' goal is to eliminate further use of pesticides and convert to organically managed parks. He said parks need to shift from a "point-and-shoot chemistry" approach to a methods that build soil health.

"Transition to organic parks, or we will work to elect commissioners who will," Henry said.

The board was told that the use of liquid herbicides has been cut by 98 percent since 2008, down to 15 gallons applied last year to 51 of the system's 6,700 acres of land and water. That was partly offset by rising use of granular herbicides, but most of that is in weed-and-feed combinations that are predominantly fertilizer instead of weed killer.

A staff presentation to the board emphasized continuing efforts since 1999 to use chemical controls as the last resort in a hierarchy that emphasizes proper plant selection and culture, mowing, and nonchemical biological controls.

Assistant Superintendent Justin Long said park forestry programs use herbicides only when a property owner requests that a boulevard ash or elm be treated. He said there's no broad spraying in neighborhood parks, but there are spot uses for weeds in paving seams or on invasive plants like thistle or buckthorn. Some small natural areas are sprayed, and athletic fields in eight sports complexes, such as Parade or Fort Snelling, get more treatment.

Commissioner Scott Vreeland said that although he supports reducing pesticide use, there are times when the ability to use them is essential. He cited an outbreak of an invasive aquatic weed in Powderhorn Lake that he said could have spread to other Minnesota lakes if not checked by a pesticide.

A switch to goats isn't a cure-all, according to one who has used them. Tim Reese, farm manager at Gale Woods Farm in Minnetrista, part of Three Rivers, said goats require good fencing, human oversight, predator protection and lots of follow-up.

Goats feed voraciously on buckthorn and garlic mustard but also on any other plant within reach.

"They love buckthorn. It's one of their favorite things. They'll stand on each other's backs to get at it," said Will Winter, who supplied the farm with some of the flock of several hundred goats he grazes as a side business.

Reese emphasized that goats were only a starting point in the farm's goal of converting a small acreage to a woodland pasture. Repeated grazing by goats knocked back the invasive vegetation, but pigs were used to feed on the following year's regrowth. People also removed stems before the area was seeded in native grasses suitable under oak trees. Sheep and cattle still graze the plot to assure that invasives don't return.

Erwin wants to try the goats, something Minneapolis Park Board commissioners Brad Bourn and Annie Young long have favored, in areas of the park system more beset by invasive species and somewhat buffered from nearby residents. The goats would be fenced in.

One place he has suggested is near the intersection of Wirth Parkway and Glenwood Avenue in Theodore Wirth Park, where tree cover was lost to a 2011 tornado, allowing buckthorn to flourish. That area also has the advantage of being outside the city limits. Current city ordinance generally excludes hoofed animals, but Erwin said some in City Hall are willing to amend that.

Steve Brandt • 612-673-4438

Twitter: @BrandtMpls