Noxious Weeds Profile - Giant Hogweed

Table of Contents

  1. Names
  2. Photos
  3. Current Status
  4. Poisonous/Cautions
  5. Distribution
  6. Growth Habit
  7. Method of Propagation
  8. Control
  9. Related Links


  • English - giant hogweed
  • French - berce du caucase
  • Latin - Heracleum mantegazzianum


Giant Hogweed
Giant Hogweed

Current Status

  • Ontario Weeds Act - noxious
  • Other provinces - no
  • Canadian Federal Seeds Act - no
  • U.S. Federal Noxious Weed - no
  • U.S. Noxious State Reg - none


  • Giant hogweed can be a serious health hazard for humans. Its watery, clear sap contains photosensitizing compounds (furanocoumarins), which, when in contact with human skin and in combination with UV radiation, can cause burning. Content varies depending on plant part, but contact should be avoided at all times. The reaction of the skin depends on individual sensitivity. After 24hrs, reddening and swelling of the skin can be noticed, which is followed by an inflammatory reaction after 3 days. Depending on individual sensitivity, effects can last for months and skin can remain sensitive to UV light for years. Research has also shown that furanocoumarins in general may be carcinogenic and teratogenic.

    Source: Nielsen, C., Ravn, HP, Nentwig, W., Wade, M. (2005) The Giant hogweed best practice manual: guidelines for the management and control of an invasive weed in Europe. Forest & Landscape Denmark, Forest & Landscape Denmark, Hoersholm.

  • Canadian Poison Plant – Listed


Growth Habit

  • Perennial

Method of Propagation

  • Reproduces only by seed


Related Links

For more information:
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