These Old World plants are valued for their striking flowers and medicinal use. They bloom nonstop in warm weather.
O. aristatus. CAT'S WHISKERS. Native to tropical and subtropical regions from India to Australia, this tender perennial gets its common name from the long white stamens that protrude from its white or pale blue flowers. In frost-free areas, the plant can grow to 5 ft. tall and 3 ft. wide; in cold-winter areas, where it's treated as an annual and must be replanted each spring, it reaches only half that size. Purple stems hold deep green, shiny, toothed leaves that are 13 in. long. Upright clusters of many flowers appear continuously in warm weather and attract bees, butterflies, and hummingbirds. Requires fertile, well-drained soil that is not allowed to dry out; it will not tolerate frost. Makes an excellent addition to the mixed border, never failing to elicit comment, questions, and admiration. Also good grown in containers.
O. labiatus 'Lilac Splash'. PINK SURPRISE BUSH, SHELL BUSH. Native to southern Africa, the spikes of this woody shrub lack the whiskers that are the hallmark of O. aristatus. However, it is similar in that it blooms from spring to frost, if there is one, and hummingbirds and butterflies can't get enough of it.