City asks residents to be on the lookout for Giant Hogweed

Guelph, ON, July 17, 2015 – The City is asking residents to be on the lookout for Giant Hogweed and its close relative Wild Parsnip.

“Both Giant Hogweed and Wild Parsnip are noxious weeds that look alike and can cause a public health hazard,” explains Martin Neumann, manager of Parks Operations. “The City is asking residents to report Giant Hogweed and Wild Parsnip on public property by contacting Parks Operations and Forestry at 519-837-5626 or sending a photo and location to All inquiries will be investigated within two business days”.

Staff removed twenty-five plants that appeared to be Giant Hogweed from the Eramosa River Park area today and will continue to monitor the area for other patches of the noxious weeds.

Giant Hogweed’s clear, watery sap has toxins that cause skin inflammation and burns when skin is exposed to sunlight, and in serious circumstances, blindness if the sap gets into eyes. The plant is harmful to both people and pets.

Residents who find Giant Hogweed or Wild Parsnip on private property are responsible for its removal. This can be done with the assistance of a professional service, such as a pesticide application company. Protective clothing, including eye protection, should be worn when handling or digging out Giant Hogweed.

How to identify Giant Hogweed

Giant Hogweed is an invasive plant from Asia that reaches a height of 10 to 15 feet (three to four metres) when in flower. Its hollow stems are two to four inches (five–ten centimetres) in diameter with dark reddish-purple spots and bristles. Giant hogweed flowers mid-May through July, with numerous white flowers clustered in an umbrella-shaped head that is up to two and a half feet (0.75 metres) in diameter. Giant Hogweed looks like Queen Anne’s lace but is considerably larger, and grows in open, undisturbed sites with abundant light, such as river or forest edges.


Photos and more information about Giant Hogweed

For more information

Martin Neumann
Manager, Parks Operations
Parks and Recreation
519-822-1260 extension 3337