The blooming period for vinca flowers, also called periwinkles, depends on what kind of vinca is involved. Perennial vincas (Vinca minor, V. major) have blue flowers except for a few cultivars with white or purple flowers, and bloom primarily in spring. Summer-flowering, or annual, vincas (Catharanthus rosea) have rose-colored flowers in the species, but cultivars have a wider range of flower colors, mostly from white through pinks, reds and purples.. Annual vincas bloom through the summer. All vincas are usually ground covers or container plants.
Native to tropical Madagascar, summer-flowering vinca, also called annual vinca, has rosy-pink flowers and glossy, oval leaves. It grows 12 to 24 inches tall and wide, suitable for ground covers, hanging baskets, containers and mass plantings. It needs hot weather and does best in full sun. It is more drought-tolerant than it looks, so avoid overwatering, and use well-draining soil to prevent root rot. Abundant flowers bloom continuously throughout the summer. Summer-flowering vinca is hardy in USDA zones 9 through 12, and is treated in lower hardiness zones as an annual.
Different color combinations and heights occur in selected lines of summer-flowering vinca. The "Carpet" series offers very short, 3- to 4-inch-tall plants that each spread to 2 feet wide. The large-flowered "Pacifica" and "Tropicana" series do well in areas with high heat and humidity, and the "Mediterranean" series has trailing growth that cascades over container edges.. "Heat Wave" is a series that tolerates drier heat. For cooler growing conditions, like greenhouse production, the "Cooler" series performs well. "Cora" is a series bred to be resistant to Phytophthora root rot. Flower colors range from intense pure red, pink, white and purple such as exhibited by the "Victory" series, to pastel pink, lilac and coral and also pure colors centered by a contrasting central eye. These all bloom from early summer to frost and are hardy in USDA zones 9 through 12.
Evergreen perennial lesser periwinkle (Vinca minor), also called creeping myrtle, is a ground cover for shady areas in USDA zones 4 through 9. Plants are 6 inches tall and spread 2 to 4 feet wide. Thin stems have medium-sized green leaves, with blue flowers in spring on the species. A number of cultivars exist. White-flowered forms are "Alba," "Albo-plena" with double flowers, and "Miss Jekyll." "Emily Joy" has pink-tinged white flowers. Plants with yellow variegated leaves are "Aureovariegata," "Golden Bowles," "Maculata," "Illumination" and "Variegata." White-margined variegated cultivars are "Albo-variegata," "Argenteo-variegata," "Ralph Shugert" and "Sterling Silver." "Flore Pleno" has double blue flowers, "Honeydew" has lavender-blue flowers, and "Atropurpurea" has reddish-purple blooms .Slower-growing cultivars like "Illumination" and "Bowles' Variety" make good container plants, with "Bowles' Variety" reblooming occasionally into summer and fall.
Big periwinkle (V. major) is a rapidly-growing perennial vine that has escaped from garden settings and is regarded as an invasive plant that is spreading to native plant communities in California. Streamside, or riparian, areas are especially vulnerable. Californians should choose other noninvasive ground covers for shady areas. Big periwinkle is also reported as being invasive in Western and Southwestern states and some Southern and Eastern states. It spreads not by seeds from the spring-blooming blue flowers but vegetatively, with roots forming at stem nodes.
- National Garden Bureau Inc.: 2002: Year of the Vinca
- Fine Gardening: Vinca minor and Cvs. (Creeping Myrtle, Lesser Periwinkle)
- University of Florida IFAS Extension: Catharanthus Roseus Periwinkle, Madagascar Periwinkle
- Floridata: Catharanthus Roseus
- University of Georgia College of Agricultural & Environmental Sciences: A Guide for Commercial Production of Vinca
- North Carolina State University: Catharanthus Roseus Cultivars
- University of Vermont: Vinca
- California Invasive Plant Council: Vinca Major (Big Periwinkle)
- Invasive Plant Atlas: Big Periwinkle
- Perennial Resources: Vinca Minor "Bowles' Variety" ("La Grave")