Contact information
For information on Lakes in Wisconsin, contact:
Division of Water
Bureau of Water Quality
Aquatic Invasive Species Contacts

Giant hogweed (Heracleum mantegazzianum) - W. Washington Rd (Station #10053181) Pop. #384

Date First Found

Giant hogweed (Heracleum mantegazzianum)

About Giant Hogweed

Giant hogweed is a herbaceous biennial or monocarpic perennial that grows as a bushy rosette for at least the first year. In general, it will bolt in the second year and grow to be 8-15’ tall with hollow, ridged stems covered in coarse white hairs and reddish-purple mottling. The plant dies after seed dispersal. It invades roadsides, empty lots and woodland edges. Due to fast growth rates, it can crowd out native vegetation. Giant hogweed prefers moist areas with some shade, particularly along stream banks, where it can lead to soil erosion and can disperse seeds downstream. Sap from leaves and stems on skin, when exposed to sunlight, can cause a phytophotodermatitic reaction consisting of severe burns and blisters.