Native to the United States and Central America, and occurring from Texas to Florida, and north to New Jersey, as well as in the West Indies.
An annual weed that reproduces from seeds. This plant can be found commonly in wet locations along roadsides, disturbed sites, or in cultivated crops, as well as along the margins of ponds, marshes, or irrigation and drainage ditches.
Mature plants may be as tall as 3 feet, with many branches that arise at right angles to the main stem. In cross section the stems are 4-angled. The leaves are long and slender, with smooth margins and pointed tips, and they grow opposite along the stem without stalks, but do have lobes on either side of the base. The small flowers occur in groups of 3 or 4, tightly attached at the base of the leaves. When opened the 4 petals are pink to red and round in shape.
Characteristicts Important to Control:
Control of excessive moisture will prevent the weed in turf or roadside settings. In naturally wet areas a systemic herbicide effectively kills the plants.