IDENTIFICATION
Annual.
Barnyard grass can grow to 1.5 m in height and has long, flat leaves
which are often purplish at the base. Most stems are upright, but some
will spread out over the ground. Stems are flattened at the base. The
seed heads are a distinctive feature, often purplish, with large millet-like
seeds in crowded spikelets.
DAMAGE
Considered one of the world's worst weeds, it reduces crop yields and
causes forage crops to fail by removing up to 80% of the available soil
nitrogen. The high levels of nitrates it accumulates can poison livestock.
It acts as a host for several mosaic virus diseases. Heavy infestations
can interfere with mechanical harvesting.
HABITAT
Barnyard grass commonly occurs along roadsides, ditches, railway
rights-of-way, and in disturbed areas such as gravel pits and dumps. It
also invades riverbanks and the shores of lakes and ponds. It occurs in
all agricultural regions of British Columbia.
SPREAD
Individual plants can produce up to 40,000 seeds per year. Water, birds,
insects, machinery, and animal feet disperse it, but contaminated seed
is probably the most common dispersal method.
