A hardy perennial vine that grows wild from Texas to Virginia, and sometimes beyond, passionflower (Passiflora incarnata) thrives anywhere it gets at least a half day of sun. It grows in ditches, and can be kept as a houseplant if you have a sunny window. The exotic purple flowers appear from early summer to autumn, and each blossom lasts only a day. If pollinated, the plants develop egg-shape fruits, which pop loudly when stamped upon-hence the common name of maypop vine. Herbalists use the fruits as a mild sedative. The state wildflower of Tennessee, passionflower is easy to grow on a trellis or as a cover for an old stump. After the vines die back in late autumn, trim away the current season's growth. New stems will sprout from root buds in spring.