Origin:
Possibly native to South America, but now occurring throughout North America except for the Rocky Mountains, and south through Central America to South America.
Biology:
A winter or summer annual, sometimes acting as a perennial broadleaf weed. The main stem is stiff and erect, and persists after foliage has died away, with flowers still present on the upper stem. It is found on areas with little other plant competition, such as poorly maintained turf, landscape, or in loose soils in disturbed areas and waste lots. Propagation is from seeds.
Identification:
Mature plants remain short, usually under 12 inches high, with several branches near the base. Most leaves are alternate and clasping the stem, oval or heart shaped. Leaf margins have fine teeth along them. Plants have a fibrous root system. Flowers are produced in the axils of the leaves either singly or in clusters of 2 or 3. There are 5 bright purple petals that are elongate oval, leading to a tubular base. The seed pods are a vase-like, oblong capsule, remaining on the stem into the late summer.
Characteristicts Important to Control:
Maintaining healthy turf will out-compete the weed, which otherwise is tolerant of a wide variety of habitat conditions.