Most of all gardeners just love Annual Vinca, as it will tolerate a wide variety of conditions and still keep producing. Other names are Madagascar or rosy periwinkle plant (Catharantus roseus) is a spectacular plant used as a ground cover or trailing accent. Catharanthus is a genus of flowering plants in the dogbane family, like Vinca and Periwinkles. Such a trouble-free delight in the garden, Vinca plants are subshrubs and have slender trailing stems, but do not grow more than 8-30 inches in height. With heat, drought and poor soil tolerance, annual vinca (Catharanthus roseus), also known as Madagascar periwinkle, is a very popular annual in the South. The plants grow 1 or 2 feet high and about the same in width. There are new spreading types that are wider and lower. Most vinca have a dense, rounded form. Vinca is grown as an annual. It will often return in following summers from self-sown seed. Annual vinca is not the same as the perennial periwinkles. Vinca is an easy-to-grow annual for beds, borders, edging and containers. Vinca prefers full sun, tolerates heat and drought and can be relied on to flower in the hottest weather throughout the entire summer. Vinca takes a long time to flower when started from seed. It should not be planted outside until the ground is very warm. If planted too early, vinca often develops fungus problems. Improper pH may increase disease problems with vinca. A pH of 5.4 to 5.8 is ideal. Good soil drainage is important to prevent disease.
Vinca does not need either deadheading or pinching to maintain its bloom and form.