A colorful, sporadic weed commonly found in fallow fields and along roadsides, these annuals are semi-parasitic on the roots of grasses.Rose-purple flowers are borne in loose racemes of six to fourteen flowers on plants two to three feet tall. The flowers are about one inch long and nearly as broad, with the throat usually yellow and spotted with purple. The leaves are linear, one to one and one-half inches long, and rough-hairy on the upper surface.
In early autumn these pretty, noticeable flowers brighten the countryside, often a vivid mass of color. In certain habitats they are so numerous that they give a distinctive pink color to open areas. In the Southeast, it is the most abundant of about fifty species of this American herb.
It was named for the celebrated herbalist, John Gerarde (1545-1611).