European Coltsfoot
Tussilago farfara
Washington State Classification
Class B — Control Required (Designated)
This is a new Class B noxious weed for 2018.
Required control in Region 1 (all western Washington counties)
Quick Reference
Identification
Growth Habit
European coltsfoot is a rhizomatous perennial, growing up to 19.7 inches, which can form extensive colonies. Plants first send up flowering stems in the spring, each with a single yellow flowerhead. Just before or after flowers have formed seeds, basal leaves on long petioles grow from the rhizomes, with somewhat roundish leaf blades that are more or less white-woolly on the undersides.
Leaves
European coltsfoot has two types of leaves: flowering stem leaves and basal leaves.
Flowers
European coltsfoot yellow daisy-like flowerhead is solitary, having yellow ray and disk flowers, at stem tips.
Fruit & Seeds
Each fertile flower can produce a single, narrow seed (cypsela), 3 to 4 mm long, having 5 to 10 ribs. One end has numerous white, hair-like bristles (pappus), that are 8 to 12 mm long and help with wind dispersal. Seed production varies greatly, with estimates ranging from 157 (per flowerhead) to 3,500 seeds (per plant).
Impact
This is a new Class B noxious weed for 2018. European coltsfoot is a rhizomatous perennial that thrives in open to shaded disturbed habitats, forming extensive colonies. It is a known weed in European agricultural systems, where it is difficult to control, as well as native plant communities. In Washington, European coltsfoot has established in riparian areas after knotweed (Polygonum species) control.
Ecology & Spread
Habitat
European coltsfoot commonly grows in open to shaded disturbed environments. Plants appear to favor moist to wet soils but can also survive in drier conditions. Herbarium and database records document European coltsfoot occurring at a limited number of locations in western Washington. Please click here to see a county level distribution map of European coltsfoot in Washington.
Spread Mechanisms
Reproduction
Plants are able to reproduce by seed as well as spread vegetatively through the fragmentation of rhizomes.
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