Giant hogweed is an invasive perennial herb from the carrot family (Apiaceae). Introduced in the early 1900’s as a garden plant, it has spread throughout much of southern and central Ontario from Southwest Asia. Hogweed populations in these locations range in size from individual to thousands of plants. Giant hogweed invasions can have a range of negative impacts on society and the environment. It poses a significant threat to human health.  

Giant Hogweed grows to an enormous size and produces large umbrella–shaped white flowers. Giant Hogweed sap can cause a condition called phytophotodermatitis, which makes skin extremely sensitive to sunlight, and can result in severe burns and blisters. It also out-competes native plants, reduces biodiversity and degrades the quality of riverbank or shoreline (commonly referred to as riparian habitats). Giant hogweed can negatively impact agriculture and is listed as a noxious weed under the Weed Control Act.