Two species of vinca vine grace gardens: greater periwinkle (Vinca major) and lesser periwinkle (Vinca minor). The severity of winter cold limits which vinca vine grows best in your region. The five-petaled flowers occur if adequate light reaches the plants, and in some cases, only when the plants reach mature size and age.
Greater periwinkle hails from the mild-climate woodlands of the western Mediterranean countries in both southwestern Europe and extreme northwestern Africa. Lesser periwinkle's native range extends into much colder regions: Europe eastward into southern Russia and the northern Caucasus Mountains in western Asia.
Both species of vinca vine become prostrate evergreen sub-shrubs with long, vine-like stems that root where they come in contact with soil. The oval, dark green leaves occur in pairs along the length of the stems and create an attractive backdrop to the five-petaled flowers that appear from mid-spring through autumn. The flower color is usually blue-violet, but purple, pale blue or white blossoms form on plants, too.
Greater periwinkle plants grow between 12 and 18 inches in height with an indefinite spread of branches, often over 10 to 30 feet in length. Lesser periwinkle grows much lower naturally, getting only as tall as 4 to 8 inches, but with an indefinite spread of its viny stems.
In areas where hardy outdoors, these plants make exceptional sprawling ground covers for shaded hillsides or expanses under large shade trees. If grown in like manner in more sunny areas, flowering increasingly and consistently occurs. Lesser periwinkle plants often grow as summer annuals in flower beds, window boxes, hanging baskets or large containers where their trailing stems create a weeping or pendulous effect.
Greater periwinkle demonstrates diminished tolerance to prolonged winter cold before dying. Rated for USDA hardiness zones 7 through 9, winter low temperatures must not drop below 0 degrees Fahrenheit in order for it to survive. Grow this species only in Sunset climate zones 5 through 24. Lesser periwinkle grows well in more regions, particularly those with colder winters. They adapt well to gardens in USDA hardiness zones 4 though 9, and in Sunset climate zones 1 through 24.
Cultivated varieties of greater periwinkle that gardener's enjoy center on variegated foliage colors. White and green leaves develop on Variegata (also known as Elegantissima), green leaves with yellowed centers occur on Maculata, and green leaves with streaking veins of yellow or ivory develop on variety Reticulata. As the leaves age the streaking fades to dark green.
More diversity exists with choices of lesser periwinkle, in both flower color and leaf variegation. White flowers develop on Gertrude Jekyll and Alba Variegata and pink buds that open to white flowers happen on variety Bowles White. Azurea Flore Pleno produces sky-blue flowers with extra petals, forming double blossoms. Perhaps the darkest plum-purple tinted blossoms occur on Atropurpurea (also called Rubra or Purpurea). Multiplex produces plum-purple flowers with extra petals, another double-flower selection.
The milky sap of both species of vinca vine contain alkaloids and must not be eaten.