Origin:
Native to the eastern United States, but also an introduced exotic species in Hawaii.
Biology:
This annual weed can be found in many roadside habitats and along moist ditchbanks. The foliage exudes a pungent smell when crushed, and has been used for both medicinal purposes as well as an insect repellent. Propagation is by seeds that are easily wind dispersed.
Identification:
Mature plants can be several feet tall, with a central stem and numerous branches. Stems and leaves are sparsely hairy. Leaves are lance-shaped and up to 5 inches long with pointed tips and toothed margins. Flowers occur in loose clusters at the ends of the stems, and are violet to pink in color.
Characteristicts Important to Control:
Physical removal is possible for individual plants. Moisture control will reduce the habitat favorable to this plant.
