Also called barnyard millet or billion dollar grass, Japanese millet is grown principally as a forage grass. It resembles barnyard grass and probably originated from that species. It makes the most rapid growth of all the millets when conditions are favorable and can ripen grain in as little as 45 days.

Japanese millet is an annual grass that grows 2 to 4 ft tall, and is commonly grown as late season green forage. Japanese millet is most useful as a long season cover and smother crop. Its fast growth and fibrous root system make it an excellent smother crop, erosion protector and trap crop. Some research has also shown that Japanese millet grows well in a mix with cowpea.