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

Names

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

Photos

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

Poisonous/Cautions

• 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 http://www.cbif.gc.ca/pls/pp/ppack.info?p_psn=195&p_type=all&p_sci=comm&p_x=px

Distribution

• It can be found throughout Ontario but is more widespread in southern Ontario. The Canadian Journal of Plant Science’s series on “The Biology of Invasive Alien Plants in Canada” http://www.ontarioweeds.com/media/pdf/page_biology_canada_weeds.pdf provides the most recent information on distribution across Canada.

Growth Habit

• Perennial

Method of Propagation

• Reproduces only by seed
  

Control

• The University of Guelph/OMAFRA partnership provides an overview of management strategies http://www.ontarioweeds.com/media/pdf/hogweed_research_summary2_2010.pdf

• Ontario Weed Gallery: Giant Hogweed
• Ontario Vegetation Management Association