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Giant Hogweed is an invasive species that has received considerable attention in the local news over the last couple of summers. It is known for its enormous size – growing from 2.5 to 4 metres (8 to 14 feet high). The plant has two major negative impacts, as a threat to biodiversity and as a public health hazard. Giant Hogweed produces a clear, toxic watery sap, which when it comes into contact with the skin of animals and humans, can make the skin more sensitive to sun, leading to possible burning or blistering.
Giant Hogweed is currently at or near the peak of its growth cycle. If you have the plant on your property, it is recommended you exercise extreme caution if you wish to control it. Giant Hogweed is full-grown now, so you are at a higher risk for exposure, and removal at this time may be less effective for long-term control. The removal of flower heads at this time can help prevent the spread of hogweed but it must be done before the seeds ripen. Do not attempt removal after the seeds are ripe! Movement of dried plant materials (seed heads) will only further disperse the seeds. You may wish to obtain professional assistance for removal, a list of contractors who are willing to control Giant Hogweed has been compiled by the Ontario Invasive Plant Council. The best time to remove this plant is in April or May when it is smaller.
Conservation Halton is tracking the spread of Giant Hogweed in its watershed, if you have this plant on your property, or see it, you can report it to us by clicking here. Conservation Halton has a page on its website where you can find plenty of information on Giant Hogweed, including the map where it has been reported, a fact sheet, and a video produced by OMAFRA to help identify Giant Hogweed. Click here to visit that page.
Giant Hogweed is just one of many invasive species in Conservation Halton’s watershed that threaten our local native species and our biodiversity. Local native plants can provide food and shelter for the wildlife that live around us, the disappearance of these plants threatens the survival of the wildlife. To learn more about Invasive Species in Ontario, visit the Conservation Halton website or the Ontario Invasive Plant Council website.