By East Kootenay Invasive Species Council

ORANGE HAWKWEED (Hieracium aurantiacum)

Orange hawkweed is one of 14 non-native hawkweed species in B.C. and is the only one with orange flowers, while all other hawkweeds, whether native or introduced, have white or yellow flowers.

This perennial primarily spreads through stolons (above-ground runners) and wind-dispersed seeds.

While new populations often start from seeds, established infestations mainly expand vegetatively via stolons.

Originally introduced from Europe as an ornamental plant, orange hawkweed forms dense mats that outcompete native vegetation. It spreads rapidly through horizontal roots, runners, and seeds, with one plant capable of producing hundreds of seeds. Agriculture, recreation, wildlife, and wind all contribute to its spread.

Key Characteristics:

Flowers: Bright orange to red, clustered together.

Stems: Upright, solitary, and hairy, ranging from 0.3 to 1.2 meters in height.

Leaves: Oblong-spatulate, forming a basal rosette, four to 20 cm long, with hairs on both sides.

Fruits: Dark, ribbed achenes with a brownish, bristly pappus, about two mm long.

Impacts:

Economic: Competes with native and desirable species, negatively affecting ranching and agriculture by reducing forage yield and quality, leading to lower stocking rates.

Ecological: Decreases biodiversity, impacts native flora and fauna, and threatens rare and protected species.

Control:

Mechanical: Mowing before flowering can reduce seed production, though soil disturbance may promote its spread.

Hand-Pulling: Small infestations can be manually removed, but care must be taken to bag and dispose of roots and stolons to prevent further spread.

Learn more.

East Kootenay Invasive Species Council photo

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