Plant Database

This nonnative biennial's leaves form a rosette the first year. It has a short fleshy taproot. Its many spreading branches have green or brownish leaves. The leaves are prickly on upper sides and cottony underneath. They are wavy, lobed and very well guarded by their spines, which also extend down the stem. 2 - 5 ft. Purple July-Sept. The flowers are more or less clustered at the ends of branches. They are dark purple, 1 1/2 to 2 inches wide and resemble purple powder puffs. The involucre is somewhat tapered and covered with spines. The seeds are topped by a circle of plume-like white hairs. This native of Eurasia is classified as a Class C weed. The seeds are an important part of the diet of many birds, especially Gold Finches and Pine Siskins. Thistle seeds are sometimes sold as wild birdseed. The Painted Lady butterfly lays her eggs on the leaves of the Bull thistle. After they hatch, they eat the leaves. Leonora Curtin Wetland Preserve