Setaria faberi is an annual grass that can reach 2-5 ft. (0.61-1.5 m) in height.
Foliage
Leaves are up to 16 in. (41 cm) long, 0.6-1 in. (15-25 mm) wide. Sheath is round with hair on margins. Blade has short hairs cover the upper surface. Ligule has a fringe of hairs. There are no auricles.
Flowers
Flowering occurs in late summer to early fall, when a green (eventually straw colored), bristly inflorescence develops. The inflorescence resembles a foxtail, hence the common name.
Fruit
The fruit are small flattened ovoids with hard coats. They usually germinate in late spring to early summer.
Ecological Threat
Setaria faberi is native to Asia and was accidentally introduced in the United States in the 1920s as a contaminant of other grain. Plants invade disturbed sites such as roadsides, landfills, fence rows and right of ways.
Herbicide Resistance
Populations of this plant exist in the United States that are resistant to ACCase inhibitors (A/1), ALS inhibitors (B/2), and Photosystem II inhibitors (C1/5).