Native to Eurasia, but now found throughout most of North America up to Alaska.
A winter and spring annual that reproduces from seeds, this weed is capable of forming extensive patches in turf, landscape, disturbed sites, or in fields and pastures.
Mature plants are generally around 1 foot in height or less, and as the leaves mature the upper areas of the plants turn reddish to purple. Stems are four-sided, and stems and leaves are covered with soft hairs. The leaves are opposite, with those on the lower plant on long stalks and on the upper plant on short stalks. The flowers are an irregular shape, with the pink to reddish-purple petals joined at their bases. The flowers occur as a whorl of several flowers arising from the bases of the leaves.
Characteristicts Important to Control:
In turf a selective broadleaf herbicide is effective, and prevention is effective with pre-emergent herbicides. Hand removal may be effective in limited infestations.