IPM1007, Revised November 2009
A biennial that produces a rosette of very large leaves during the first year and branched, upright stems with many burs during the second year of growth. Primarily a weed of pastures and other noncrop areas but is becoming increasingly problematic in no-till cropping systems. Rosette leaves are broadly heart-shaped, 6 to18 inches long, 4 to14 inches wide, with hollow petioles and wavy, toothed margins. Stem leaves are much smaller, alternate, and egg-shaped. Small purple to lavender flowers occur in clusters at the ends of branches or from the region between the stem and leaf petioles. Flowers dry to a bur that has distinctly "hooked" bracts.
Order publications online at http://extension.missouri.edu/explore/shop/ or call toll-free 800-292-0969.