Hawkweed

Also known as:
Hieracium Species
Family:
Asteraceae
Origin:
Europe

General description

The hawkweed group comprises small hardy perennials which colonise tussock lands. Perennial mat-forming herbs with milky sap. Root system always with horizontal or ascending rhizomes, often also with stolons. Plants form tight, interconnected rosettes. Basal leaves usually slightly toothed, with bristly hairs above and star-shaped hairs below, 25-150 x 6-50 cm, dull green to dark green above, usually paler (occ purplish) below. Stems 10-75 cm tall, usually thin, stem leaves small (occ absent). Flowers dandelion-like, 1-many, lemon or yellow (orange, purple when dry, in H. aurantiacum and H. x stoloniflorum), occ with red stripe on outer face, Oct-May. Seeds with fluffy, dirty-white hairs, 4-8 mm long, also Oct-May.

Terrestrial. Disturbed shrubland and forest, beech forest, tall and short tussockland, fernland, alpine and volcanic plateau herbfield, bare land, riverbeds and streambanks, rocky outcrops.

Seed by wind, clothing and animal pelts. Rhizomes and stolons via water movement, contaminated soil and machinery

Grow rapidly in tussock grasslands, displacing native species. Form dense, long-lived mats in low-growing plant communities, exclude almost all other species. Allelopathic.

Site management

Planting a dense band of shrubs at infestation edge can prevent vegetative spread. Exclude livestock at all times, as healthy tussock communities are less likely to become infested. Begin control at windward end (at seeding time) of infestation. Combination of the above methods may improve competitiveness of native species.

Recommended approaches

1. Ensure biocontrol agents are present wherever possible.
2. Dig out (small spots): dispose of rhizomes.
3. Weed wipe (100ml clopyarid/L or 250ml 2,4-D Ethylhexyl Ester/L or 1g metsulfuron/L). Active growth only.
4. Spray (25ml clopyralid/10L (Do not use in home gardens) or 50ml 2,4-D ethylhexyl Ester/10L or 5g metsulfuron/10L). Active growth only.

Caution: when using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.

RPMS status

Surveillance - Whole Region
National Pest Plant Accord species - nationwide
hawkweed - Main species image