The Blooming Period for Vinca Flowers
The booming period for vinca blossoms, also called periwinkles, depends on the type of vinca is demanded. Perennial vincas (Vinca minor, V. major) have blue flowers except for some cultivars with purple or white flowers, and blossom primarily in spring. Summer-flowering, or yearly, vincas (Catharanthus rosea) have rose-colored flowers in the species, but cultivars have a larger range of flower colors, mostly from white through pinks, reds and purples. . Yearly vincas bloom through the summer. All vincas are generally ground covers or container plants.
Summer-Flowering Vinca
Native to tropical Madagascar, summer-flowering vinca, also called annual vinca, has rosy-pink flowers and shiny, oval leaves. It grows 12 to 24 inches tall and wide, suitable for ground covers, hanging baskets, containers and mass plantings. It requires warm weather and does best in full sun. It’s more drought-tolerant than it appears, so avoid overwatering, and utilize 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 can be handled in reduced hardiness zones within an annual.
Catharanthus Cultivars
Different color combinations and heights occur in selected lines of summer-flowering vinca. The “Carpet” string offers very short, 3- to 4-inch-tall plants that each spread to 2 feet broad. The large-flowered “Pacifica” and “Tropicana” string perform well in areas with high heat and heat, and the “Mediterranean” string has trailing increase that cascades over container borders. . “Heat Wave” is a string that tolerates heat. For cooler growing conditions, like greenhouse production, the “Cooler” string performs nicely. “Cora” is just a string regarded as being resistant to Phytophthora root rot. Flower colors range from intense pure crimson, pink, white and purple such as exhibited by the “Victory” series, to purple purple, lilac and coral as well as pure colors centered by a contrasting eye. All blossom from early summer to frost and are hardy in USDA zones 9 through 12.
Lesser Periwinkle
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 broad. Thin stems have medium-sized green leaves, with blue flowers in spring to the species. Lots of cultivars exist. White-flowered forms are “Alba,” “Albo-plena” with double flowers, and “Miss Jekyll.” “Emily Joy” has pink-tinged white blossoms. 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 blossoms, and “Atropurpurea” has reddish-purple blooms . Slower-growing cultivars such as “Illumination” and “Bowles’ Variety” make good container plants, with “Bowles’ Variety” reblooming sometimes into summer and fall.
Big Periwinkle
Big periwinkle (V. major) is a rapidly-growing perennial vine that has escaped from garden settings and is considered as an invasive plant that is spreading to indigenous plant communities in California. Streamside, or riparian, areas are especially vulnerable. Californians should pick other nonstick ground covers for shady areas. Big periwinkle can also be reported as being invasive in both Western and Southwestern states and a few Southern and Eastern states. It disperses not by seeds from the spring-blooming blue flowers but vegetatively, with roots forming at stem nodes.