Skip to content
NorthFactsFacts first, Canada's reference desk
Nature

Giant Hogweed

What is giant hogweed?

· James MacDonald

Key facts

Scientific name Heracleum mantegazzianum[1]
Plant family Apiaceae[1]
Plant type Biennial or perennial herb[1]
Height 14 feet or more[1]
Leaf width Up to 5 feet[1]
Flower head diameter Up to 2 1/2 feet[1]

Giant hogweed is a very large invasive plant in the carrot family, scientifically named *Heracleum mantegazzianum*, that can cause painful skin burns and scarring through its sap.

Context

Giant hogweed is a very large invasive plant in the carrot family, scientifically named *Heracleum mantegazzianum*, that can cause painful skin burns and scarring through its sap [1]. It is a biennial or perennial herb that can grow very tall and has large divided leaves and white flower heads [1]. The plant is native to the Caucasus region of Eurasia/Asia [2]. Its hollow stems have dark reddish-purple blotches [1]. The sap can cause painful, burning blisters when skin is exposed to sunlight [3]. Giant hogweed flower heads resemble “Queen Anne’s Lace on steroids” [2].

Documented claims

  • Giant hogweed is invasive. [1]
  • Contact with the sap can cause painful burns and scarring. [1]
  • The sap can cause painful, burning blisters when skin is exposed to sunlight. [3]
  • It is native to the Caucasus region of Eurasia/Asia. [2]
  • It has dark reddish-purple blotches on hollow stems. [1]

Questions and answers

What happens if you touch giant hogweed?

Touching the sap can cause painful burns and scarring [1]. When skin exposed to the sap is then exposed to sunlight, painful, burning blisters can form [3].

How poisonous is giant hogweed?

Giant hogweed is not poisonous to eat, but its sap is dangerous. Contact with the sap can cause painful burns and scarring [1], and the sap can cause painful, burning blisters when skin is exposed to sunlight [3].

Is Queen Anne's lace the same as giant hogweed?

No, they are different plants. Giant hogweed flower heads resemble “Queen Anne’s Lace on steroids” [2], but giant hogweed is much larger and has distinctive dark reddish-purple blotches on its hollow stems [1].

Sources

  1. [PDF] GIANT HOGWEED - Maine.gov — maine.gov (retrieved August 3, 2026)
  2. Species Spotlight - Giant Hogweed (U.S. National Park Service) — nps.gov (retrieved August 3, 2026)
  3. Giant Hogweed - National Invasive Species Information Center (NISIC) — invasivespeciesinfo.gov (retrieved August 3, 2026)

Sources last checked August 3, 2026. · More in Nature