Giant Hogweed (Heracleum mantegazzianum)
Description: A large broadleaf weed in the carrot family (Apiaceae), typically 8-10' in height but can be taller. Sap may cause servere skin irritation.
Life cycle: Biennial - first year forming only vegetative growth. In second year forms the tall flowering stems. Dies after second year.
Habitat: Along railroads, roadsides, rights-of-ways, vacant lots, streams, rivers, uncultivated or waste lands and agriculture areas.
Leaf: Very large, jagged, deeply lobed leaves may be 5 feet long.
Stem: Hollow, ridged stalks are 2-4 in. in diameter, light green with purple spots.
Flower: Large, white, umbrella-shaped flower clusters that can grow up to 2.2' in diameter.
Fruit: Seeds form in the flower clusters, dry, flattened, oval shape
Root: Extensive taproot.
The problem is….an aggressive competitor. It outcompetes native plant species because of its size, rapid growth and heavy seed production. It contains a substance within its sap that makes the skin sensitive to ultra violet light which is a public health hazard. Large watery skin blisters usually appear 15 to 20 hours after contact with the sap and sunlight. Do not handle this plant without protection. Can be confused with poison hemlock but is much larger.
