Culture
Winter hardy to USDA Zones 10-11 where it is easily grown in average, medium, well-drained soils in full sun. Tolerates part shade, but best flowering in full sun. Best in organically rich, fertile soils. In St. Louis, grow in the ground as bedding annuals that are replaced in the garden each spring or in pots/containers as frost-tender perennials that are overwintered indoors. May be easily grown from seed started indoors in late winter approximately 8-10 weeks before last frost date. During the growing season, water regularly (allow soils to dry somewhat between waterings) and feed monthly. To overwinter, bring pots/containers inside before first frost to a bright, cool (59-50°F) location and reduce watering. Cuttings may also be taken from favorite plants in late summer for overwintering. Also may be grown as a houseplant in a sunny room with high humidity.
Noteworthy Characteristics
Pentas lanceolata, commonly called Egyptian star cluster or star flower, is native from Yemen to East Africa. It is a tropical woody-based perennial or subshrub that grows 3-6’ tall in its native habitat, but more typically to 1-2’ tall in beds or containers in the St. Louis area. It is a many-branched, somewhat sprawling plant that features 4” wide rounded clusters (corymbs) of star-shaped flowers over a long summer to frost bloom. Elliptic to lanceolate dark green leaves (to 6” long). Flowers are pink, magenta, lilac or less commonly white. Highly attractive to hummingbirds, butterflies and other pollinators.
Genus name comes from the Greek word pentas meaning a series of five with reference to the flower parts being in fives instead of fours as in related genera.
Specific epithet means lance- or spear-shaped.
'Butterfly Orchid' features dense, terminal clusters of star-shaped, violet-pink blooms held on upright stems. Highly attractive to hummingbirds and butterflies. Mature plants can reach 22" tall and 18" wide.
Problems
Watch for aphids and spider mites. Whiteflies can be particularly troublesome on indoor plants.
Uses
Beds and borders, containers, and houseplant. Also may be effectively gown indoors under artificial lights.