Hawkweeds

Hawkweeds are plants in the genus Hieracium (family Asteraceae). They include many perennial herbs native to Europe and Asia, with numerous species introduced elsewhere as ornamentals or weeds. In some regions they are considered invasive due to rapid spread and competition with grasses and native wildflowers.

They typically form a basal rosette of hairy leaves and produce erect flowering stems up to about 50 cm tall. Each flower head contains multiple yellow florets that are ligulate (strap-shaped), giving a daisy-like appearance. The overall look can vary among species from small, low clumps to tall, bushy forms. Leaves are often hairy and may be clasping along the stem.

A notable feature of many Hieracium species is apomixis, seed production without fertilization, enabling rapid clonal spread and complicating classification. The genus is large with many species and subspecies, and numerous synonyms exist, making precise identification difficult.

Native to Eurasia, hawkweeds occupy meadows, pastures, roadsides, forest margins, and other open sites. They have become established in North America, New Zealand, and other regions where they can tolerate disturbed soils and grazing.

In pasture and grassland systems hawkweeds can displace grasses and native wildflowers, reduce forage quality, and form dense stands that are difficult to eradicate. Their apomictic reproduction allows persistence even when parent plants are removed.

Control strategies emphasize prevention of spread and early removal. Methods include mowing before seed set, careful herbicide use, and reseeding with competitive grasses. Due to their reproductive strategy, complete eradication can be challenging and often requires integrated management and long-term monitoring.