Yellow Starthistle

Centaurea solstitialis

A winter annual or sometimes biennial forb. Rosettes with 6-28 leaves close to the ground, yellow flowers with spine-tipped middle and outer bracts.

Life Forms	Forb
Habitats	Abandoned fields Farm fields Forest openings Grasslands Oak woodlands Orchards Pastures Railroad tracks Rangelands Roadsides Vineyards
ODA Listing	A
Soil and Moisture Conditions	Dry to moist Low fertility soil Nutrient rich soil Well drained
Suggested Actions	Report to Oregon Invasives Hotline
Shade Preference	Full sun
Mature Height	0.3-3+'
Distribution	Found in much of the western US but not widespread in the Willamette Valley.
Control	Small infestations can be pulled before plants set seed. Tillage can be used on roadsides but may damage desirable species in wildlands and rangelands. Grazing at the right time may be an option (see FS.USDA.gov link for details). Six biological control agents established in the US can suppress yellow starthistle but are unlikely to eliminate it. Chemical management is most effective when used as one facet of a long term management plan.
Reproduction and Spread	Reproduces and spreads by seed.
Introduced	Originally from the Mediterranean, was introduced to North America in the early 1800s.
Look Alikes	knapweeds, Canada thistle, mullein
Impact	Degrades rangelands and pastures. Spines injure grazing animals.
More Info	https://www.fs.usda.gov/database/feis/plants/forb/censol/all.html#Control