Common Burdock
Common burdock is a member of the Aster or Sunflower family, Thistle tribe. It is an introduced biennial which reproduces by seeds. In the first year of growth the plant forms a rosette. The second year the plant is erect. The stem is stout, grooved, rough, has multiple branches, and grows to 2-6 feet tall.
The leaves are alternate, dark green, smooth above, whitish green, and woolly hairy beneath. The flowers are purple or white in numerous heads. The head is enclosed in a prickly bur, an involucre, composed of numerous smooth or wooly bracts tipped with hooked spines.
Burdock grows along roadsides, ditch banks, and neglected areas. This plant is a very serious threat to sheep as the burs can significantly damage the quality of the wool. Burdock is very common in central and north central Colorado.
The leaves are alternate, dark green, smooth above, whitish green, and woolly hairy beneath. The flowers are purple or white in numerous heads. The head is enclosed in a prickly bur, an involucre, composed of numerous smooth or wooly bracts tipped with hooked spines.
Burdock grows along roadsides, ditch banks, and neglected areas. This plant is a very serious threat to sheep as the burs can significantly damage the quality of the wool. Burdock is very common in central and north central Colorado.