Giant Hogweed

Genus: Heracleum

Species: mantegazzianum

Description: Member of the carrot or parsley family grows 3-5 meters (10-15 ft) tall.The white flowers are on a large umbrella-shaped head that can be nearly 1 meter (2 ½ ft) in diameter. Flowers mid-May to July. Plant also has a stout dark reddish-purple stem and spotted leaf stalks.

Where it grows: Grows in riparian areas and roadsides. Wooded or open-space areas between residential communities.

How it spreads: Winged seeds spread by water, soil movement or by animals; can remain viable in the soil for over 10 years.

What it threatens: Major public health hazard. Sap can cause blistering of the skin and permanent scarring; sensitivity to light may also occur. Crowds out desirable native, forage and crop plants with its aggressive growth.

More information: USDA website

Disclaimer - Clean Water Services does not endorse or recommend specific herbicides for use in controlling these species. To protect water quality, always follow herbicide label directions and obey application laws when using any herbicide.