Native to Madagascar, India, and tropical Asia, Madagascar periwinkle blooms continuously in hot weather, thriving in both humid and dry heat. Bushy plant grows 1112 ft. high and wide, with upright stems clothed in glossy green leaves and adorned with phloxlike, 112-in. flowers in pure white, pink, rose, or white with a rose or red eye. Bloom goes on all summer, but by autumn the plant gets leggy and flowering is spotty. Survives winter in central and south Florida, where it has escaped cultivation and naturalized. Self-sows readily, especially in sandy or gritty soil.
Recent breeding has produced plants with larger blossoms in a wider range of colors, including vibrant shades of red, lavender, and purple. Flowers of some new types sport overlapping petals, giving them a fuller, more rounded look. Pacifica and Cooler series are compact, 12- to 15-in. plants with large (2-in.) flowers. The Tropicana series features blooms in shades of pink and coral on foot-tall plants. The Stardust series bears orchid, pink, or raspberry-red flowers centered with a white starburst.
Variations in form among Madagascar periwinkles include shorter and more compact types and those with trailing habits. The Little series grows 810 in. high; the Carpet series grows 48 in. tall, creeping to 112 ft. wide. Plants in the Mediterranean series grow 56 in. high and can spread 212 ft. wide; they're useful as a seasonal ground cover or in hanging baskets. Blossom colors include apricot, pink, rose, lilac, and white. The disease-resistant Cora series has mounding and trailing forms, many colors, and extra-long bloom; plants grow 1416 in. tall.
All types bloom the first season from seed sown early indoors or in a greenhouse or cold frame, but most people buy transplants at garden centers. Unfortunately, many of the newer hybrids seem more susceptible than their predecessors to wilt and rot diseases caused by planting in heavy, wet soil. Be sure to plant in loose, fast-draining soil, and take care not to crowd plants.
Madagascar periwinkle was formerly known botanically as Vinca rosea, and many people still call it by the name vinca.