Beware of a Dangerous Invasive Weed -- Updated

May 12, 2008

By Mike Owen, Department of Agronomy

Upon further investigation about the location of “local” infestations of the highly invasive giant hogweed, it was determined that the Wisconsin location is in Iron County which is located at the northern boundary between Wisconsin and the Upper Peninsula of Michigan (see colored area on the map). Gogebic County, Michigan also has or had infestations of giant hogweed. The U.S. Forest Service is working diligently to eradicate these populations.

The good news is that identified locations of giant hogweed are not that close to Iowa.The bad news is that giant hogweed is aggressive and adapted to Iowa habitats. Thus it is still important to be aware of the possibility of giant hogweed invading Iowa and contact the ISU Extension or the Iowa Department of Natural Resources if you suspect that you have this nasty plant.

A recent news release from the Weed Science Society of America warns of a particularly dangerous invasive weed, giant hogweed.

The weed is related to species that are commonly found in Iowa, however giant hogweed is highly invasive and is capable of causing considerable damage to anyone who comes in contact with the plant. While giant hogweed has yet to be discovered in Iowa, populations have been found in Wisconsin.

Thus it is possible that giant hogweed populations may exist in northeast Iowa. There are a number of links that can be used to find more detailed information about this weed. Also, pictures of  four common weedy relatives of giant hogweed found in Iowa are included for comparison purposes. 


Giant Hogweed


Wild Parsnip


Water Hemlock


Queen Anne's Lace


Cow Parsnip


Mike Owen is a professor of agronomy with research and extension responsibilities in weed management and herbicide use.

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