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Home > Weeds > Giant Hogweed

Giant HogweedHeracleum mantegassianum

An invasive perennial and a public health hazard: Contact with sap followed by sun exposure can cause painful blistering. Grows in moist soil, especially in ditches and ravines in both sun and shade.

mature giant hogweed plants leaves of giant hogweed stem of giant hogweed
Numerous white flowers grow in umbrella-shaped clusters up to 2 feet across. Flowers mid-June to late July. Leaves are unevenly lobed and up to 5 feet wide. Plants can reach a height of 10 to 15 feet when in flower. Hollow stems are 2 to 4 inches in diameter and have dark reddish-purple blotches.

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[Photos: Maine Department of Agriculture]

It is the policy of the State of Maine to minimize reliance on pesticides. The Maine Department of Agriculture and the Maine IPM Council encourage everyone to practice integrated pest management and to use pesticides only as a last resort. The mention of pesticides in the fact sheets linked to these pages does not imply an endorsement of any product. Be sure that any product used is currently registered and follow all label directions.