Yellow starthistle
(Centaurea solstitialis)
Yellow starthistle originated from Northern Spain. It is a winter annual that is blue-green in color, has a vigorous taproot, and produces bright yellow flowers with sharp, stiff spines surrounding the base of the flower that extends up to ¾ of an inch long. Yellow starthistle grows from 1 inch tall to 4 feet tall. Basal leaves are 1-3 inches long and deeply lobed while upper leaves are smaller and narrower. Stems appear winged and both stem and leaves have a slight whitish nap covering them. Yellow starthistle spreads by seed with a single large plant producing up to 100,000 seeds. Plumed and plumeless seeds disperse at different times.
Access the EDDMapS distribution map for Yellow starthistle in Colorado by clicking the image below.
Access the USGS INHABIT suitability model for Yellow starthistle in Colorado by clicking the image below.
INHABIT is an online tool created by the USGS that provides species distribution models for various invasive plant species. The models associate known occurrences of a species with environmental characteristics to create maps that predict habitat suitability, and these maps can be used to assess the potential spread of noxious weeds. Learn more about INHABIT: https://www.usgs.gov/centers/fort-collins-science-center/science/inhabit-a-web-based-decision-support-tool-invasive