Origin:
Native to the eastern United States, and found throughout the eastern half of the U.S. except for the extreme northern states.
Biology:
A perennial plant which is found in moist, even semi-aquatic habitats in low and shaded areas. Propagation is from seeds as well as the spreading rhizomes, and it may become invasive in ornamental beddings.
Identification:
Mature plants can be over 3 feet tall, upright and with several branches off the main stem. Leaves are opposite and are triangular and wrinkled, with toothed margins and very hairy surfaces. Flower heads occur in open clusters at the ends of the stems, with each flower head about ½ inch in diameter and pink to purple or blue.
Characteristicts Important to Control:
Generally not an invasive weed, but where it occurs and is not wanted it can be controlled with a systemic herbicide. Physical removal would require the elimination of underground rhizomes.
