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revised April 01, 2020

Health Protection


Giant Hogweed

Giant Hogweed is an invasive plant that has been found in Brampton, Caledon and Mississauga. If Giant Hogweed sap touches your skin or your eyes, it could have harmful health effects.

What does it look like?

Giant Hogweed looks similar to cow parsnip and can be about 4.5 to 6 metres (15 to 20 feet) tall. The plant has:

  • Hollow stems with dark reddish-purple splotches and coarse white hair
  • Leaves as wide as 1.5 metres (5 feet) with hairs on the underside
  • Flattened oval shaped fruit
  • Small white flowers in the summer

Giant Hogwood images Giant Hogwood images
Giant Hogwood images Giant Hogwood images

What are the symptoms and health effects?

If you touch clear watery sap from the plant’s stem or hairs, you could experience a reaction within 48 hours:

  • On skin, sap can cause sensitivity to sunlight. This can cause painful blisters and burns, which could lead to pigmented purple and black scars.
  • In eyes, sap can cause temporary or permanent blindness.

Giant Hogwood images

Burn caused by giant hogweed

www.Bugwood.org, www.forestryimages.org.
This photo is licensed under a Creative Commons Attribution 3.0
United States License

What should I do if I come in contact with it?

If clear watery sap from the plant’s stem or hairs touches your skin or eyes:

  • Wash the affected areas immediately.
  • Avoid touching your eyes.
  • Stay out of the sun for at least 48 hours after contact with the sap to prevent a skin reaction.
  • Seek medical attention.

What should I do if I find it?

If you find Giant Hogweed in a park or other area, call the Parks Department at your local area municipality:

If you find Giant Hogweed on your property, remove the plant as soon as possible. We recommend you hire a lawn care professional to remove the plants. If you wish to remove the Giant Hogweed yourself, it is very important to take the following safety precautions:

  • Wear protective clothing, including gloves, long sleeves, pants, eye protection, rain coat and boots.
  • Avoid getting sap on your skin.
  • Immediately remove any flower heads to prevent seeds from falling and dispersing.
  • Sever the plant roots 8 to 12 cm below the soil surface.
  • Dispose of all plant parts in double-bagged sealed garbage bags. Label the bags with the words “Giant Hogweed.” Call the Region of Peel at 905-791-9499 (or 905-584-2216 in long-distance areas) to arrange for special pick-up, free of charge.
  • DO NOT compost or put in your yard waste or green bin containers. Giant Hogweed will not be collected at the curb.
  • Afterwards, wash the clothes you wore to remove the plant.
  • Return to the plant site periodically to remove any new plant growth.

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Revised: April 01, 2020

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