field of soybeans with pigweed
U of A CES Pasture Weed Control Database
The Pasture Weed Control Database contains the same information and pictures included in the Miscellaneous Publication MP-522. The weeds are arranged alphabetically by scientific name because common names vary. For example, in Arkansas, Eupatorium capillifolium, is variously called, Dogfennel, Cypress Weed, and Texas Cedar.

Spiny Pigweed, Amaranthus spinosus

Amaranthus spinosus

Pigweeds are prolific seed producers. Single plants are capable of producing thousands of seeds. Given adequate rainfall, pigweed seeds germinate throughout the summer. All emerged pigweeds may be killed by a herbicide treatment only to be replaced by another flush of seedlings. Repeat applications will be needed for full-season control. Spray when the pigweeds are less than 12 inches tall. Cimarron Plus, metsulfuron 60 DF, Grazon P+D, GrazonNext HL and Dicamba + 2,4-D, and 2,4-D amine all -provide good control of seedling pigweed. There are metsulfuron resistant populations of pigweed in Arkansas. Use a growth regulator herbicide if you suspect ALS resistance.