Origin:
Native to Eurasia, this plant was introduced to North America and now is found in nearly every state, with the exception of the extreme southeast.
Biology:
An annual weed reproducing from seeds. It is a very common weed along roadsides, in cultivated fields, in pastures and fields, as well as any disturbed site. A number of its chemical ingredients can cause serious toxic problems in livestock when it is eaten.
Identification:
Under good growth conditions plants may grow to 6 feet in height. It is a bushy plant with many branches that grow erect or laterally. Most of the stems and branches are covered with soft hairs, and the branches may develop a reddish color as they mature late in the season. Leaves are small, narrow, and lance shaped and are alternate. The tiny flowers grow in short clusters of 3 to 6 flowers, at the ends of the branches, arising from the leaf axils.
Characteristicts Important to Control:
Large plants should be removed, preferably prior to the maturation of their seeds. Chemical control can be effective with a systemic or contact herbicide, and pre-emergent control can be accomplished with the appropriate material.