A vinca is any member of the genus Vinca, which contains 7 to 12 species native to Europe, North Africa and parts of Asia. Vincas are generally perennial. Trailing stems are characteristic of many vincas, as are simple opposed leaves. Vinca flowers generally have five petals apiece, joined into a tube at the base of each flower. The flowers are blue or blue-purple, but can be pink, rose or white.
The most commonly cultivated vinca species are Vinca major and Vinca minor. The latter is most often grown as a perennial groundcover and sometimes called by the common names of "periwinkle" or "myrtle." Confusion arises over Madagascar periwinkle, which some authorities place in the Vinca genus (Vinca rosea), while others consign it to the related genus Catharanthus (Catharanthus roseus). No matter which genus it belongs to, Madagascar periwinkle is a member of the Apocynaceae or dogbane family, like its vinca relatives. Unlike Vincas major and minor, Madagascar periwinkle has stiffer stems, a more erect growth habit and flowers in shades of white, pink or rose. Other Apocynaceae species include oleander, amsonia and asclepias (milkweed).
The genus Vinca was first described by Linnaeus in 1753. The name "vinca" comes from the Latin word "vincio" meaning "to bind", probably referring to the twining stems of many members of the genus. Cultivated for centuries, Vinca minor was probably introduced into Europe before 1000 AD. It arrived in this country during colonial times, as did Vinca major, first introduced in the United States in 1789. Both Vinca major and minor were used outdoors as ground cover plants and V. major was also used in pots and as a conservatory specimen. Vinca can sometimes be found growing rampant in old, untended cemeteries.
Vinca major and minor as well as Vinca rosea have traditionally been used for medicinal purposes, especially as tonics, astringents (applied externally) and as anti-hemorrhagic remedies (internal and external). The most useful medicinal vinca is rosea. Extracts from the plant have been used over the centuries by herbalists to treat a range of problems from asthma to high blood pressure. In the 20th century, Vincristine, an alkaloid derived from Madagascar periwinkle, was used to treat various forms of cancer.
Tender Madagascar periwinkle is grown as a flowering annual in cold winter climates. Its glossy leaves and near continuous blooming habit make it a wonderful pot or bedding plant. The trailing stems of Vinca major also make it attractive spilling over the sides of pots or hanging baskets. The glossy leaves, rapid growth habit and ground-covering ways of Vinca minor make it a favorite of landscapers who want to cover a lot of earth in a relatively short time. Vincas major and minor are tolerant of shade as well.
Breeders have worked to develop strains of Madagascar periwinkle with large flowers as wide as 2 inches across and contrasting centers. Flowers on newer Vinca minor varieties may be wine, white or bright blue with doubled petals and/or variegated foliage in combinations that include gold or white and green. Variegated forms of Vinca major are also popular.
Vinca minor can become invasive if left unchecked. All parts of Vinca rosea are toxic when ingested.