The world of gardening often uses common names that lead to confusion, especially regarding plants known as Periwinkle and Vinca. These names are frequently used interchangeably across garden centers and online resources. While the terms are closely related, understanding the difference requires exploring the formal system of plant naming known as taxonomy. This overlap often causes gardeners to incorrectly assume all plants bearing the common name are the same species.
The Definitive Answer Taxonomy and Common Names
The primary difference between Vinca and Periwinkle is the distinction between a scientific genus and a common name. Vinca is the formal botanical genus name used by scientists for a small group of species within the Apocynaceae family. “Periwinkle” is the widely accepted English common name applied to plants within the Vinca genus, specifically the European groundcovers. Because common names lack the precision of scientific classification, “Periwinkle” has also been popularly applied to other plants that share a similar appearance.
Differentiating the Groundcovers
The two most common species of true periwinkle used for groundcover are Vinca minor and Vinca major, both trailing subshrubs. Vinca minor, often called Dwarf Periwinkle, is the more cold-hardy species, thriving in USDA hardiness zones 4 through 9. It features smaller, lance-shaped leaves and comparatively smaller, five-petaled, blue-violet flowers.
Vinca major, or Bigleaf Periwinkle, is less cold-tolerant, generally suited for zones 6 through 9, but handles more heat. This species features significantly broader, sometimes heart-shaped leaves. Both species are prized for their glossy, evergreen foliage and aggressive spreading habit, which allows them to form a dense, weed-suppressing mat. This aggressive nature has led to both species being classified as invasive in certain regions.
The Other Periwinkle
A separate source of confusion is the Madagascar Periwinkle, botanically classified as Catharanthus roseus. Although it is in the same family (Apocynaceae), it belongs to a different genus, Catharanthus, yet shares the common name “Periwinkle.” Unlike the trailing Vinca groundcovers, C. roseus grows as an upright, herbaceous annual or tropical perennial. It is identified by its shrub-like growth and prolific, warm-weather flowering in shades of white, pink, or rosy-purple. The confusion stems from historical taxonomy, as Catharanthus roseus was once formally named Vinca rosea before being moved to its current genus.