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    Giant Hogweed - Destroy Nuisance Weeds

    Giant HogweedWhat is it?

    • An invasive plant.
    • The sap of Giant Hogweed can negatively affect human health.
    • Can be found along roadsides, vacant lots and stream banks.

    Giant Hogweed Sap Can Cause:

    • Serious skin inflammation (photodermatitis).
    • The skin to be highly sensitive to UV rays due to a chemical called furanocoumarins.
    • Skin blisters, redness, scarring, and other discolouration that can last for years.
    • Temporary or permanent blindness if sap enters the eyes.
    • Reactions that can occur for up to 48 hours after contact.
    • Heat and moisture (sweat) can enhance the reaction.

    What does it look like?


    • 1 to 4 metres (3 – 14 feet)


    • Large white clusters of small flowers
    • Umbrella shaped
    • 30 to 60 cm in diameter (1 to 2 feet)


    • Up to 1 metre (3 feet) in diameter
    • Sharp coarse teeth
    • Compound leaves deeply divided into lobed toothed leaflets
    • Produces watery sap


    • Rough and bumpy
    • Course white hairs emerging from bumps
    • Hollow
    • Purple/red splotches

    How can I be exposed to the sap of giant hogweed?

    • Touching or brushing up against the plant.
    • Touching clothing or pets that have come into contact with the plant.
    • The sap can become airborne by pulling, cutting or mowing giant hogweed. This can cause sap to get in the eyes.

    What do I do if I accidentally come into contact with giant hogweed?

    • Wash the affected area immediately with soap and water.
    • Keep the affected area out of the sun for at least 48 hours.
    • Seek medical attention.

    What we do?

    If you find giant hogweed on municipal property please contact Public Works at
    905-873-2601 Ext. 2603.

    If you suspect Giant Hogweed is on your property:

    • Keep children and pets away from the area.
    • You are encouraged to contact a licensed weed exterminator. They can be found under “Weed Control Services” in the Yellow Pages.
    • If you choose to remove giant hogweed yourself, USE EXTREME CARE.
    • Information on Giant Hogweed removal methods and how to report a sighting can be found at
      DO NOT compost the plants. 
    • DO NOT place out for curbside collection either as Leaf & Yard Waste, Green Cart or waste material.
    • Giant hogweed must be taken to the Halton Waste Management Site for safe disposal.
    • Monitor the area for future growth.
    • Community Standards By-law 2008-0138 Part 3, Section 8 Nuisance Weeds states "Property Owners are required to destroy and remove all nuisance weeds and weed seeds on their land." Also see amendment: By-law No. 2014-0031.

    For more information on the Giant Hogweed please follow these links:



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