Culms 20-100 cm; nodes 6-7. Blades 4-12 mm wide. Panicles usually 3-8 cm, producing around 600-800 caryopses. 2n = 18.
Setaria viridis var. viridis is an aggressive adventive weed throughout temperate North America. It is the most common annual representative of Setariain the Flora region.