Orange Hawkweed Hieracium aurantiacum History and Impact
This aggressive invader from Europe is also known as devil's paintbrush. It outcompetes many native species by forming dense, monotypic stands, or competes with forest understory plants. As a Class B noxious weed, its control is required in King County. Biology and Morphology Easily recognized by its showy red-orange flowers, it is a perennial with lance-shaped, hairy leaves that form a basal rosette. The erect, bristly stem grows up to twelve inches tall, producing 5 to 30 flowers at the tip. Occasionally there are one or two small leaves on the stem. The entire plant contains a milky juice. The root system is fibrous.
After starting to flower, each plant produces severalwhite-fuzzy stolons that extend 4 to 12 inches and form the next generation of plants. It thrives in disturbed areas such as roadsides, gravel pits and pastures. It can also invade meadows and forested areas and is well-adapted to life at higher eleventations. Usually found in sunny areas, it is somewhat shade tolerant. It spreads by seeds, stolons and rhizomes.

For information on hawkweed identification and control, please download our hawkweed weed alert (1.76 MB Acrobat file). If you find orange hawkweed in King County, please notify us through our online infestation form. To find out where we have records of this weed in King County, use our interactive noxious weed map and search for orange hawkweed. For more information about orange hawkweed, please see the written findings by the WA State Noxious Weed Control Board. For information on controlling orange hawkweed in King County, please read the hawkweed best management practices (82 KB Acrobat file). |