- Heracleum mantegazzianum is a herbaceous biennial or monocarpic perennial that can grow up to 15-20 ft. (4.3-5.8 m) in height. The stem is hollow and usually blotched with purple. Both the leaf stalks and stem produce pustulate bristles. The stem can be 2-4 in. (4.8-9.6 cm) in diameter.
- The leaves are ternate or ternate-pinnate with pinnately lobed lateral segments. They can be up to 9.8 ft. (3 m) in breadth.
- Heracleum mantegazzianum flowers from June-July. The inflorescence has many white florets (with petals about 0.4 in. [1 cm]) that form a flat-topped umbel. Each inflorescence can have a diameter of up to 2.5 ft. (0.72 m).
- The fruits are dry and elliptic, measuring 0.3-0.4 in. (8-11 mm) long and 0.25-0.3 in. (6-8 mm) wide. The fruits have brown resin canals that can be up to 0.04 in. (1 mm) in diameter.
- Ecological Threat
- Heracleum mantegazzianum can outcompete species for habitat, especially in riparian zones, and it may cause increased soil erosion. This plant is on the federal noxious weed list because of its poisonous sap. This sap makes skin very sensitive to UV radiation, causing blistering and severe burns. Caution should be taken when handling this weed. Removing it manually becomes very difficult because of the danger caused by its sap.
- Domestic Programs Pest Evaluation - USDA APHIS PPQ
- Fact Sheet - USDA APHIS PPQ
- Invasive Plant Atlas of New England - University of Connecticut
- Federal Noxious Weed Disseminules of the U.S. - USDA-APHIS
- Weed of the Week - USDA Forest Service
- Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service
- Fact Sheet - Ontarios Invading Species Awareness Program
- Best Management Practices - Ontarios Invading Species Awareness Program
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EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org
Invasive Listing Sources
- California Noxious Weeds
- Commonwealth of Pennsylvania, Department of Conservation and Natural Resources, 1994.
- Connecticut Invasive Plant List
- EDDMapS Ontario
- Faith Campbell, 1998
- Federal Noxious Weeds
- Florida Noxious Weeds
- Great Lakes Early Detection Network
- Idaho Noxious Weeds
- Invasive Plant Council of New York State
- Massachusetts Noxious Weeds
- Mid-Atlantic Exotic Pest Plant Council, 2005
- Minnesota Noxious Weeds
- Native Plant Society of Oregon, 2008
- New Hampshire Prohibited Invasive Species
- Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
- North Carolina Noxious Weeds - Class A
- Ohio Noxious Weeds
- Oregon Noxious Weeds
- Pacific Northwest Exotic Pest Plant Council, 1998
- Pennsylvania Noxious Weeds
- South Carolina Noxious Weeds
- USDA APHIS Regulated Pest List
- Vermont Noxious Weeds
- Virginia Invasive Plant Species List
- Washington Noxious Weeds
- WeedUS - Database of Plants Invading Natural Areas in the United States
- Wisconsin's Invasive Species Identification, Classification and Control Rule
|Common Name Reference:|| USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|
|Scientific Name Reference:||USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.|