Barnyard grass is an annual grass reaching 1' - 4' in height. Leaves are smooth and light green in color. Length ranges from 6" - 12". Roots are fibrous and shallow. The flower panicles are upright and bear many branches that are green-purple in color. Seeds are tan to brown.
The stem is flat and erect with roots at its nodes. The leaves are linear with a broad round base narrowing at the tip. The flower head is reddish, purplish, pinkish or greenish. The seed head is windmill-shaped and the seeds are short with stiff awns. It completes its development in 42-64 days. Each plant can produce up to 40,000 seeds. The young weeds resemble rice seedlings. Prior to seedhead formation, Fall Panicum (Panicum dichotomiflorum) and barnyardgrass are often confused due to their similar growth habit and appearance. 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.
Although Barnyard grass is more of a problem with agricultural areas, it does sometimes show up in landscapes. Will usually disappear from the lawn with regular mowing.