Source: Idaho's Noxious Weeds by Robert H. Callihan & Timothy W. Miller
BACKGROUND
Orange hawkweed (Hieracium aurantiacum) is native to Europe. Distribution of this weed has likely been assisted by flower enthusiasts due to its beauty. Orange hawkweed spreads by seed, stolonsA creeping stem along the surface of the ground, and rhizomeA creeping, underground stem and generally inhabits moist grasslands.
DESCRIPTION
Orange hawkweed is a perennialPlant that lives for more than 2 growing seasons weed with shallow, fibrous roots. Leaves are hairy, spatula shaped, up to 5 inches long, and almost exclusively basalAt the base of plant or plant part. Extensive stolonsA creeping stem along the surface of the ground create a dense mat of hawkweed plants that practically eliminates other vegetation. Stems are usually leafless, although occasionally a small leaf appears near the midpoint. Stems may reach a height of 1 foot and bear up to thirty ½ inch flower heads near the top. Flowers are red to orange and appear in late May or June. Stems and leaves exude a milky latex when cut or broken. Seeds are tiny and plumedA hairlike or featherlike structure, often on a seed.
DISTRIBUTION
Orange hawkweed is found in many eastern states and also from western Washington to Wyoming.
CONTROL
No biological control agents are available for orange hawkweed. When selective herbicides are applied in the spring and followed with nitrogen fertilizer, grass competition can keep this weed suppressed.