giant hogweed

Apiales > Apiaceae > Heracleum mantegazzianum Sommier & Levier

Giant hogweed is a tall (up to 15-20 ft. [4.6-6.1 m]), herbaceous, biennial plant that invades disturbed areas across both the Northeast and Pacific Northwestern United States. Giant hogweed is designated as a Federal Noxious Weed, because it produces sap that causes skin sensitivity to UV radiation and leads to blistering and severe burns. The large stem is hollow and usually marked with purple blotches. The leaves are deeply lobed, sharply pointed, and up to 5 ft. (1.5 m) wide. Flowering occurs in late spring to early summer. The white flowers are on a large umbrella-shaped head at that can be up to 2.5 ft. (0.8 m) in diameter. Giant hogweed can invade a variety of habitats but prefers moist, disturbed soils such as riverbanks, ditches and railroad right-of-ways. Giant hogweed is native to Europe and Asia. It was first introduced into the United States in 1917 for ornamental purposes.


Identification, Biology, Control and Management Resources

  • Weeds of the Week - USDA Forest Service, Northeastern Area, Forest Health Protection

Selected Images from Invasive.org

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Plant(s);
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Foliage;
Jan Samanek, State Phytosanitary Administration, Bugwood.org
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Foliage;
Donna R. Ellis, University of Connecticut, Bugwood.org
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Plant(s);
Thomas B. Denholm, New Jersey Department of Agriculture, Bugwood.org
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Feature(s); Stem cross-section
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Stem(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Plant(s);
Donna R. Ellis, University of Connecticut, Bugwood.org
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Fruit(s); Mericarp (7)9-12 mm long x 6-8(10) mm broad, strongly flattened dorsally
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Seed(s);
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Fruit(s);
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Fruit(s);
Jan Samanek, State Phytosanitary Administration, Bugwood.org
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Flower(s);
Terry English, USDA APHIS PPQ, Bugwood.org
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Flower(s);
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Flower(s);
Thomas B. Denholm, New Jersey Department of Agriculture, Bugwood.org
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Infestation; in flower
Jan Samanek, State Phytosanitary Administration, Bugwood.org
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Infestation;
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Infestation; In winter
Barbara Tokarska-Guzik, University of Silesia, Bugwood.org
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Plant(s);
Randy Westbrooks, U.S. Geological Survey, Bugwood.org
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Damage; burn caused by plant
USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org
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Control;
Terry English, USDA APHIS PPQ, Bugwood.org
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Control;
Thomas B. Denholm, New Jersey Department of Agriculture, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • Federal Noxious Weed List
  • California - Noxious Weed Law
  • Connecticut - Noxious Weed Law
  • Massachusetts - Noxious Weed Law
  • New Hampshire - Noxious Weed Law
  • North Carolina - Noxious Weed Law
  • Ohio - Noxious Weed Law
  • Oregon - Noxious Weed Law
  • Pennsylvania - Noxious Weed Law
  • South Carolina - Noxious Weed Law
  • Texas - Invasive Plant List
  • Vermont - Noxious Weed Law
  • Washington - Noxious Weed Law
  • Mid-Atlantic - EPPC List
  • Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species
  • Invasive Plants of the Upper Midwest
  • Invasive Plant Atlas of New England
  • Midwest Invasive Plant Network


External Links


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USDA Forest Service Bugwood University of Georgia