Toxic Hogweed: State looking for giant poisonous plants

Brian Kooper of the USDA and Matt Bushman study a patch of hogweed found in a backyard planter in Wakefield in 2004. Photo: USDA

Brian Kooper of the USDA and Matt Bushman study a patch of hogweed found in a backyard planter in Wakefield in 2004. Photo: USDA

By Howard Meyerson

Giant hogweed, an illegal and toxic non-native plant has been known to give state and federal officials heartburn now and then. But homeowners, hunters and hikers who may stumble upon it are being advised to report it and give the plant wide berth so as not get burned themselves.

“The toxin from it burns the skin and feels like a hot iron on your arm,” said Peter Carrington, assistant curator of the W.J. Beal Botanical Gardens at Michigan State University. “You can get burned pushing through a thicket of it. And that will change your whole day. The burns can take months to heal.”

Giant hogweed, or giant cow parsnip as it known, is a member of the carrot family. But it ranks right up with poison ivy and poison sumac as a health hazard, according to the Michigan Invasive Plant Council. The organization first reported about the weed in 2003. The group was formed in 1999 by a federal executive order signed by then President Bill Clinton.

Cow parsnips may grow to three or four feet tall, but giant hogweed can get to be 15-feet high with five-foot-wide leaves. It is covered with fine fuzz that carries a toxic sap. The  toxic effects are triggered by ultra-violet light, or sunlight.  Get the sap on your skin and walk in the sun and a serious case of blisters is likely to follow.

Giant hogweed is not a huge Michigan problem according to state and federal officials who track invasive plants. It is a much bigger problem in Pacific Northwest states. Here, there is far more garlic mustard on the ground. But unlike that leafy plant which can be used in cooking, giant hogweed is a serious public health danger. It is listed on the federal noxious weed list which prohibits its possession, sale and transport.

A popular ornamental plant

“It’s been growing in Michigan for about 50 years,” said Ian Shackleford, a botanist with the Ottawa National Forest in western Upper Peninsula where the largest Michigan infestations are found.

“It was a popular ornamental plant back then, a garden curiosity. Someone brought it in.  We’ve been eradicating it because it is a public health nuisance.”

There are 22 Gogebic County sites where giant hogweed has been reported. None are in the Ottawa National Forest, according to Shackleford. Most of those plants have since been eradicated, but eight sites were found and treated in 2012.

The plant has been reported at 60 sites statewide, from Detroit to the western Upper Peninsula, according to Michigan Department of Agriculture and Rural Development records. It has appeared in small numbers in several Lower Peninsula counties including Ingham, Berrien, Muskegon and Manistee counties.

No more federal funds for eradication 

Agriculture officials said federal money available for eradication dried up in 2012. Michigan was annually spending approximately $10,000 in federal funds to treat giant hogweed sites.

“Our funding was eliminated and we have no program anymore,” said Mike Phillip, pest survey program specialist with the Michigan Department of Agriculture and Rural Development. “It’s one we would like to be involved with because of the health hazard, but it’s not in the cards.

“Most of the sites where it is located are small, maybe one or two plants and there are a few larger sites. On the whole it is still a very rare plant.”

More information about identifying giant hogweed and who to contact is available online at: Click Consumer Information in the left column, then Human Health, then Giant Hogweed. Additional information is available from MSU Extension Service at:  Type “giant hogweed” into the upper left search box.


Copyright © 2013 Howard Meyerson

About Howard Meyerson

After more than 30 years in the outdoor writing business, you would think I'd know better.
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2 Responses to Toxic Hogweed: State looking for giant poisonous plants

  1. glenn warners says:

    What do you do if you find it???


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