A summer annual with thick stems that may reach 5 feet in height. One of the few grass weeds in which ligules are absent. Found throughout the United States, Canada, and Mexico as a weed of many agronomic crops, nurseries, landscape, and turf. Rolled in the shoot, smooth and without ligules or auricles. Leaves range from 4 to 20 inches in length and may be 5-30 mm wide.
Leaves have a distinct white midvein that becomes keeled toward the basal potions of the leaf.
A few short hairs may occur at the leaf bases. A fibrous root system. Seedhead a terminal panicle ranging from 4 to 16 inches in length. However, the characteristic absent ligule of barnyardgrass helps to distinguish this weed from most other grasses in both the seedling and mature stage of growth.