Updated on June 11 at 2:12 p.m. CT
Milwaukee County is home to more than 15,000 acres of parkland. Keeping those spaces green and healthy is daunting, especially as funding diminishes and park crews are cut. While many people cherish public green spaces, some worry about the pesticides that Milwaukee County Parks uses to manage the land.
Turns out the Milwaukee County Parks, Energy and Environment Committee is listening. On Tuesday, June 11, the committee unanimously called for the parks department to develop a written pesticide policy that will be public.
Jon Canavan is in charge of turf throughout the parks system — from golf courses to Juneau Park's 15 acres that hug the bluff above Lake Michigan. The park features two imposing statues and a lush canopy of trees. Its friends group planted and cares for a small but profuse pollinator garden.
“We really don’t treat anything here,” says Canavan.
He points to Juneau’s sea of dandelions as exhibit a.
“The only pesticide we’d be using is a little bit of Roundup in the weed beds and around a few of the light poles, stuff like that. As far as a broadcast herbicide/fertilizer, we don’t use them in open spaces like this,” Canavan says.
And if you’re a dog park person, Canavan says not to worry. “I know people are sensitive to their dogs and I understand, so we just let [dog parks] be,” he says.
Canavan says the parks system has tamped down chemical applications in recent years. He says there’s more than one reason. The first: they’re expensive.
"As budgets tighten, we use less and less," Canavan adds, "And people are thinking more about the green spaces. Honey bees do like clover and they love dandelions. It’s a great food source for them."
When park workers do targeted pesticide applications, those areas are properly marked. “If we do treat an area, you’ll see the flags up saying '24-hour notice following the law of Wisconsin,' " Canavan says.
Canavan says you’re most likely to see those flags in Milwaukee County Parks’ natural areas, such as Bender and Falk Parks.
They’re managed by Brian Russart who says he relies on many volunteers and his small staff. “Right now we have four full-time people for natural areas to manage a 10,000 acres,” Russart says.
As for the amount of pesticides he applies, Russart says “I looked back at 2017 at the pesticides we used, and we applied 15 gallons of herbicide to manage 10,000 acres. So, it’s very laser specific.”
Over his 10-plus-year tenure, Russart says his team has built a comprehensive management program.
“We have an internal reference guide for each invasive species we manage … looking at the most effective chemicals for them, what are the amounts to be used for active ingredient. We also look at the phenology because each invasive species is vulnerable at a certain time of year and your treatments are most effective,” he says.
Russart says the plan is paying off.
“I’ve definitely seen those areas that were filled with aggressive invasive species 11 years ago: The woodlands are coming back to life, the spring ephemerals are showing up again, the migratory birds and the species using these sites is increasing,” Russart adds, “So, it’s showing a very positive trend in areas that we are managing.”
Russart says pesticides and herbicides help protect wildlife habitat by keeping invasive species at bay.
“If we stop treating invasive and applying pesticides, the ecology of a lot of our sites would degrade and go backwards because invasive species are the number two cause of wildlife habitat in the U.S.,” Russart says.
Yet, he says he continues to learn, including from mistakes. About two-and-a-half years ago, his team applied an herbicide to drive down invasive species on a two-acre area within Wehr Nature Center in Franklin. Three hundred trees unexpectedly died.
“Wehr Nature Center, an unfortunate situation there and we’re working to mitigate that. We’ve changed where we use the herbicide, just to be safe,” Russart says.
He says the tree loss did have an unexpected silver lining. A native plant called small flowered leafcup popped up and the federally endangered rusty patched bumble bee is appearing on the park’s landscape.
UW-Extension weed scientist Mark Renz thinks it’s important for residents to realize that every management choice Milwaukee County or any parks system makes comes with pluses and minuses.
“How do we manage them in a way that is acceptable to the community that is using that park. Do we use herbicides? Do we not use herbicides? Do we get heavy equipment in, do we not? Do we burn? There are positive and negative aspects with all of those,” Renz says.
He’s looking for ways to better educate the public to the importance of strategically controlling invasive plants — not only for people’s enjoyment of green space but also the greater health of the ecosystems we share.
Renz says Milwaukee County stands out in Wisconsin as a leader in parks managment, but that doesn't stop some people from worrying about its use of pesticides and herbicides.
UW-Madison plant pathologist Paul Koch says he understands the concern. He says while products are rigorously tested for years before going to market, people and their pets should still stay away from freshly applied chemicals.
“That’s why … you have to keep those little signs up … You try to keep people off the treated areas for one to two days after treatment [because] it can dry on the plant and be absorbed by the plant,” Koch says.
He says when properly applied, for example not right before a significant rain storm or when temperatures soar into the 90s, the pesticides are designed to break down “in a relatively short amount of time.”
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