Originally from the mountains of Central Asia, giant hogweed made its debut in New York about 100 years ago as a dramatic ornamental plant. It's been spreading ever since, becoming a serious pest in the Northeast and the Pacific Northwest, and it's making inroads into the Mid-Atlantic.
Hogweed's winged seeds use several methods of dispersal. They can float downstream for three days and germinate in sunny, damp soils along waterways. Wind, animals and misguided gardeners have also disseminated seeds, which can remain viable in the soil for 10 years.
Giant hogweed was among many foreign plants introduced to Britain in the 19th century, mainly for ornamental reasons. It is now widespread throughout the British Isles, especially along riverbanks. By forming dense stands, they can displace native plants and reduce wildlife interests.
It has also spread in the northeastern and northwestern United
States and southern Canada.
It is equally a pernicious invasive
species in Germany, France and Belgium, overtaking the local species. It
was introduced in France in the 19th century by botanists,
where it is much appreciated by beekeepers.
In Canada, the plant has been sighted in British Columbia,
Alberta, Ontario, Quebec, New Brunswick and Nova Scotia. It has been seen in
Quebec since the early 1990s. The plant's spread in Ontario began in the Southwest and was seen in 2010 in the Greater Toronto Area and Renfrew
County near Ottawa.