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Science & Nature • Invasive Species

Giant Hogweed

Giant hogweed (*Heracleum mantegazzianum*) is a large herbaceous plant in the carrot family Apiaceae.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Giant hogweed (*Heracleum mantegazzianum*) is a large herbaceous plant in the carrot family Apiaceae. Native to the Caucasus region of Eurasia, it has become an invasive species in parts of Europe and North America, including Canada. The plant is known for its height and for sap that can cause severe skin reactions when exposed to sunlight.

Description

Giant hogweed is a very tall herbaceous plant with large compound leaves, a stout stem with dark blotches, and a broad umbrella-like white flower cluster. It is one of the largest species in the Apiaceae family.

Distribution and habitat

The species is native to the Caucasus region of Eurasia but has naturalized in parts of Europe and North America. It commonly grows in moist, sunny disturbed habitats such as riverbanks, roadsides, vacant land, and field edges.

Ecological and health impact

Giant hogweed is considered invasive because it can crowd out other vegetation and spread aggressively. Its sap contains chemicals that can cause painful burns, blistering, and scarring after skin exposure to sunlight.

Management

Because of its public-health risk and invasive behaviour, giant hogweed is regulated or controlled in many jurisdictions. Management generally focuses on preventing seed spread and removing established plants carefully.

Key facts

  • Giant hogweed is a member of the carrot family and is scientifically named *Heracleum mantegazzianum*.
  • It is native to the Caucasus Mountains and surrounding region.
  • It was introduced to Britain and North America as an ornamental plant in the 19th and early 20th centuries.
  • The plant has escaped cultivation and spread along roadsides, riverbanks, fields, and other disturbed sites.
  • Its sap can cause phytophotodermatitis, a skin reaction that becomes worse after sunlight exposure.
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Canadian context

Giant hogweed is an invasive species in Canada and a public-health concern because contact with the plant’s sap can cause severe skin reactions. Canadian readers may encounter it in disturbed habitats such as roadsides and riverbanks, especially in parts of eastern and western Canada.

Frequently asked questions

What is giant hogweed?
Giant hogweed is a large plant species, *Heracleum mantegazzianum*, in the carrot family. It is known for its size and for sap that can burn skin when exposed to sunlight.
Where is giant hogweed native to?
It is native to the Caucasus region of Eurasia.
Why is giant hogweed dangerous?
Its sap contains furocoumarins, which can cause severe skin irritation and burns after sunlight exposure. Eye exposure can also be harmful.
Is giant hogweed found in Canada?
Yes. It has spread to parts of Canada and is treated as an invasive species.
How tall can giant hogweed grow?
It can reach about 4 metres tall, with very large leaves and flower heads.
How did giant hogweed spread outside its native range?
It was introduced as an ornamental plant and later escaped cultivation into the wild.

References

  1. Wikipediahttps://en.wikipedia.org/wiki/Heracleum_mantegazzianum
    Supports: Scientific name, common names, native range, plant family, and introduction history.
  2. Britannicahttps://www.britannica.com/plant/hogweed
    Supports: Invasive status, size, toxicity, and sap-related skin effects.
  3. Minnesota Department of Agriculturehttps://www.mda.state.mn.us/plants/pestmanagement/weedcontrol/noxiouslist/hogweed
    Supports: Scientific name, native range, and ornamental introduction history.
  4. Ohio State University Extensionhttps://ohioline.osu.edu/factsheet/anr-35
    Supports: Life cycle, habitat, native range, introduction history, and spread in North America.
  5. New York State Department of Environmental Conservationhttps://www.dec.ny.gov/nature/animals-fish-plants/plants/harmful-plants/giant-hogweed
    Supports: Physical description, native range, invasive status, and health hazards.
  6. National Invasive Species Information Centerhttps://www.invasivespeciesinfo.gov/terrestrial/plants/giant-hogweed
    Supports: Common name and scientific name.