IDENTIFICATION
Annual.
Hemp-nettle has clusters of lipped, tube-like flowers which occur
in the angle between stem and branch and can be white, pink, or purple.
Mint-like leaves are prominently veined and bristly, and stems are squared
and hairy. Mature plants grow to 0.5 m.
DAMAGE
Hemp-nettle infests grain fields, canola, and pastures, reducing
yield through competition with crops for nutrients and moisture. Its small
seeds contaminate small grains and are difficult to remove. It acts as
an alternate host for a potato fungus and several nematodes.
HABITAT
It is most abundant on moist, rich, black soils. In British Columbia,
hemp-nettle is found in cultivated fields, pastures, roadsides,
and disturbed habitats, but also in wooded areas and forest margins. It
is present in all agricultural regions of the province.
SPREAD
Hemp-nettle is spread primarily by wind and through agricultural
operations such as seeding and harvesting. Seed can also be spread through
contaminated crop seed and livestock feed.
