What if I come across Giant Hogweed?
Anyone who sees a giant hogweed plant is advised to contact a landscape professional to have it removed. Cowbrough recommends having a professional properly identify the suspected plant to ensure it is Giant Hogweed. “Over half of the submissions that OMAFRA receives are from clients claiming they have Giant Hogweed, but it’s not hogweed,” says Cowbrough. Proper identification can be obtained by submitting a photo to Weed Info: Canada’s Online Weed Information and Identification Resource.
If you find it in your garden and choose to remove it yourself, make sure you wear synthetic, waterproof clothing, including long sleeves and pants, as well as gardening gloves and eye protection. Remove the flower heads to prevent seed growth and dispersal and then cut the plant’s root eight to 10 cm below the soil surface. Don’t compost the plant. Instead, put the plant’s remains in double-bagged garbage bags. Once everything has been cleaned up, periodically check the site to make sure there aren’t any hogweed seedlings trying to reclaim the spot. Continue to monitor the area during the next few growing seasons. Hogweed can easily reseed itself and seeds may be lying dormant in the soil, waiting for an opportunity to invade your garden again.
“Landowners can also purchase glyphosate products (like Roundup) to control weeds that are poisonous to the touch, such as poison ivy, wild parsnip and giant hogweed,” Cowbrough says. Although using these types of products should be used as a last resort, they can be effective at killing the offending weed.
What do I do if I’m exposed to Giant Hogweed?
If you come into contact with giant hogweed, seek immediate shelter since exposure to the sap makes human skin hypersensitive to sunlight. Thoroughly wash exposed skin with soap and water. If your skin reacts to the sap, seek medical attention. If the sap comes into contact with your eyes, seek immediate medical attention since the sap can cause temporary or permanent blindness.
- Giant Hogweed identification videos are now available on the OMAFRA website: Giant Hogweed identification and Giant Hogweed removal
- Government of Nova Scotia: Giant Hogweed – An Alien Invasive Species in Nova Scotia
- Government of British Columbia: Aggressive Ornamentals – Giant Hogweed
Anja Sonnenberg is a horticulturist who writes about the fun she has in her garden on her blog, A Gardener’s Playground.