Hawkweeds (Hieracium spp.) are perennial plants with 14 non-native species recorded in BC, and are difficult to identify among the 8 native hawkweed species. One of the 14 non-native species, orange hawkweed (Hieracium aurantiacum) is currently the only hawkweed considered regionally noxious under the Weed Control Act. Most hawkweeds have yellow flowers. Invasive hawkweeds are found throughout most forest regions and regional districts in British Columbia. The regional districts east of the Rocky Mountains, Northern Rockies, and Peace River Regional Districts only have a few known invasive hawkweed sites and efforts to prevent further establishment and spread are actively underway. Orange hawkweed is regionally noxious in the East Kootenay, Central Kootenay, Columbia-Shuswap, Thompson-Nicola, Bulkley Nechako, and Cariboo Regional Districts.
Hawkweeds have bright orange, orange-red, or yellow ray flowers with several flower heads in clusters at the top of each plant. Leaves are long and oval-shaped, and cluster in a rosette formation at the base of fibrous, black-haired stems. Stems contain a milky fluid. Hawkweeds can grow up to 30-60 centimetres in height at maturity.
Hawkweeds spread through aboveground runners, horizontal roots, seeds, and root buds. Recreationalists, pack animals and hay contribute to new infestations. Hawkweeds flourish in well-drained, course-textured soils, and are found at low- to mid-elevations in BC. They can invade natural open areas and disturbed sites, including roadsides, pastures, and clearings. Hawkweeds’ main impact is on the forest industry, with the risk of establishment and spread along roads or areas that are not reforested. They can replace native vegetation in open, undisturbed natural areas such as meadows, reducing forage and threatening biodiversity.
Refer to Invasive Hawkweeds T.I.P.S. for information on prevention and control methods.