Origin:
Native to tropical Americas, and now widespread throughout much of North America.
Biology:
An annual weed reproducing by seed, and a problem weed in virtually all kinds of crops, as well as landscape, roadsides, ditch banks, and empty lots and waste areas. Roots are shallow, and dry plants may break free of the soil and be scattered by the wind, much like tumbleweed or Russian Thistle.
Identification:
Mature plants are more open than most other pigweed varieties. They are multiple branched off of the central stem, and can grow to 4 feet in height. Stems are light green to whitish, with alternate leaves. The leaves grow to 2 inches long and have wavy margins and prominent veins. Leaves are light green on top and sometimes tinged with reddish on the lower surface. Flowers are in small clusters that grow on very short stalks, and arise from the base of the leaves. Flowers are green and very small, and have 3 spiny bracts at their base.
Characteristicts Important to Control:
Annuals with propagation only from seed, but the mobility of the mature plant with strong winds easily spreads the seeds over large areas.
