Giant Hogweed

Giant Hogweed

(Heracleum mantegazzianum)

French common name: Berce du Caucase

Description:  

Giant Hogweed is a very large flowering plant (up to 3 m/10 ft) that belongs to the carrot family. This invasive plant resembles Queen Anne’s Lace, and became an ornamental garden species. This plant grows over 5-7 years, and produces a large umbrella shaped head of white flowers that produce thousands of seeds per plant.

Problem:  

CAUTION Giant Hogweed has a phytotoxic sap that can produce 3rd degree burns on skin when exposed to sunlight, so management of this plant requires caution. This invasive plant establishes rapidly in roadsides and ditches, and poses a human health risk when growing in public areas. 

Species identification:

Giant Hogweed is a large plant, growing from 2-5.5m with large, broad leaves with very spikey edges. This plant also has a large stem (3-8 cm in diameter) with dark purple/reddish splotches and very coarse white hairs all over the stem. In late summer, the plant produces a large umbrella shaped head of flowers up to 80cm across.

How it’s spread:  

This plant was introduced as a garden species and has been moved into new areas through dumping of garden clippings or movement of garden materials. If out in an area that may have Giant Hogweed, it is important to Play, Clean, Go before moving to a new area. Clean off all equipment, shoes, tires, etc to prevent spreading invasive plant parts.  

Use extreme caution when handling or removing this plant, and wear protective equipment as required. If you believe you have been exposed to Giant Hogweed sap, immediately wash the area with cold water and soap and remove from sunlight.