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Beware of wild parsnip in Wisconsin

By LeAnn R. Ralph

COLFAX  —  Although it has yellow flowers in a shape reminiscent of Queen Anne’s Lace, the last thing you want to do is pick it for a wildflower bouquet.

Wild parsnip (Pastinaca sativa) is an invasive plant spreading mostly along the roadsides in West Central Wisconsin that can cause huge, burn-like blisters on the skin.

In this area of Wisconsin, the worst spots are along state Highway 25, Highway 72, Highway 29, and Interstate-94, said Chris Gaetzke, a conservation planner with Dunn County who is an expert on invasive plants and works with the Lower Chippewa Invasives Partnership (LCIP).

The juice in wild parsnip plants causes what dermatologists call “phytophotodermatitis” —  that is, an inflammation of the skin caused by plant that is made worse by exposure to sunlight.

The blisters on the skin can take weeks to heal, may require cortisone injections in severe cases, and can cause discolored scars that can take years to fade away.

The wild parsnip plant has a flower head that looks like upside-down yellow umbrella, Gaetzke said.

The plants can grow up to four feet tall and have a long, thick taproot.

The best way to kill out wild parsnip, if you do not want to use chemical weed killers, is to use a spade shovel to cut the tap root several inches below the ground’s surface, Gaetzke said.

If the flower heads have not yet produced seeds, you can leave the plants laying on the ground. If the flower heads have started to produce seeds, put the plants in a plastic bag and take them to a landfill, he said.

Taking the seed heads to the landfill is the best way to ensure that wild parsnip does not seed itself in again, Gaetzke said.

In all cases, anyone working around wild parsnip should wear long sleeves, long pants and gloves, Gaetzke noted, adding that you should never touch the plant with your bare hands.

Weed whacking or mowing wild parsnip is a bad idea.

Gaetzke said he has heard of people ending up with wild parsnip being sprayed on their lips, faces and hands from weed whacking the plant.

Burning wild parsnip also is a bad idea because if you inhale the smoke, you could end up with blisters in your lungs, he said.


Kathy Stahl, a landowner in the Town of Colfax who was instrumental in forming the Lower Chippewa Invasives Partnership, also is working to help educate area residents about wild parsnip and other invasive plants.

Dunn County Conservationist Dan Prestebak said Stahl had approached the land and water division in July of 2011 asking for assistance in developing a weed management group.

“I give Kathy all of the credit … today we have the LCIP (Lower Chippewa Invasives Partnership), a non-profit conservation organization holding events in several counties each year and educating lots of landowners about invasive plants, including wild parsnip,” Prestebak said.

“Many people have no clue about the stuff, and it has exploded in our area,” Stahl said.

“Given its harmful effects on people, its invasiveness, and how far along it is in flowering now, I wish people would use herbicide to at least kill next year’s plants or take great care in mowing so as not to spread the seeds even further,” she said.

“Escort” is the most effective herbicide to kill wild parsnip and it is relatively inexpensive, Stahl said.

One local company, 4 Control out of Menomonie, also has experience with eradicating wild parsnip, she said.

“(Lee Shambeau) can professionally spray the stuff for those people who have a large infestation and cannot or do not want to personally use herbicides,” Stahl said.

Shambeau is highly respected by the state Department of Natural Resources, other agencies and LCIP, she said.

“That doesn’t mean there aren’t other good professionals, but I don’t know about them,” Stahl said.

Highway help

The Dunn County land conservation office has been working with the Pepin County and Dunn County Highway Departments to put the roadsides on a mowing schedule where wild parsnip is a problem to help control the invasive plant.

For people living along a state or county highway where wild parsnip is growing, it would be best to let the highway department mow it, Gaetzke said.

If wild parsnip can be cut before the plants go to seed, then eventually the plants will die out, he said.

Wild parsnip has a two-year life cycle, and the plants growing now are from seeds that were in the ground previously, Gaetzke said.

Although he said he is not aware of any research indicating how long wild parsnip seeds remain viable, Gaetzke noted that garlic mustard seeds can be viable for up to seven years in the ground and that yellow or white sweet clover seeds can survive in the ground for up to 50 years.

The invasive wild parsnip plant came from Europe initially. It has no natural predators, and “it explodes in growth,” Gaetzke said.

Other invasives

In addition to wild parsnip, the LCIP website lists five other target species for this area: leafy spurge; common buckthorn; Japanese knotweed; garlic mustard and spotted knapweed.

LCIP received a grant from the Wisconsin Department of Natural Resources in 2013 to purchase an equipment trailer and equipment for removing invasive plant species.

According to the LCIP website, any group in Dunn, Eau Claire, Pepin and Pierce counties can use the equipment or the entire trailer.

Equipment in the trailer includes a variety of gloves, different kinds of saws and pruners, faceshields, goggles, safety glasses and litter bags.

For more information about LCIP, the equipment trailer and invasive plants, visit