Vinca (Catharanthus roseus), also known as Madagascar periwinkle, is a bushy perennial of African origin. Vinca grows 1 1/2 to 2 feet high with a 2-foot spread and naturalizes in USDA Hardiness Zone 10. Elsewhere, vinca is often cultivated as an annual. Vinca flowers are about 1 1/2 inches wide and 1 inch long, five-petaled, and range in color from rose, pink, mauve or white, on thin, branching stems. Vinca leaves are glossy-green and 1 to 2 inches long. Propagate vinca from seed or stem cuttings. Pinching back vincas encourages bushiness.
Light and Climate
Vinca flowers prolifically during warm months and tolerates hotter temperatures better than most other flowering ground covers, according to a University of Florida IFAS fact sheet. Grow vincas in full sun for best growth, but vinca tolerates light shade as well. Vinca leaves curl during harsh summer weather, but the plants are tolerant of parched conditions and will recover in the evening. Vincas will not survive freezing temperatures.
Soil and Water
Set vinca transplants outdoors when weather is warm , after all danger of frost has passed. Grow vincas on a variety of well-drained soils (clay, sand, acidic, slightly alkaline, loam), but preferably moist and of average fertility. Water when soil starts to dry out. Mature plants tolerate dry conditions but grow better with average soil moisture. Growth and flowering is reduced with excessive watering or rainfall. A dose of liquid fertilizer once a month is recommended (follow label instructions). Mulch plants in dry weather with 2 to 3 inches of bark, chips, shredded leaves or other mulch, if desired.
Problems and Pests
Vincas are generally easy to grow but require a few measures for the best growth. Avoid watering plants late in the day to reduce development of fungal problems. Watering early allows surface moisture to evaporate. Root rot because of excessive soil moisture causes decay of lower stems and roots. Excessive soil fertility reduces growth and flowering--only fertilize periodically. Blight is a condition causing brown or black spots on leaf edges that eventually cover the entire leaf. Remove infected plants and transplant new ones further apart when replacing.