The question of whether periwinkles are perennials is often confusing because the common name refers to two distinct groups of flowering plants. Some plants called periwinkle are true, cold-hardy perennials, while others are tender perennials almost exclusively grown as annuals. Both types share visual similarities and belong to the same plant family, but their ability to survive winter depends entirely on the specific plant.
Identifying the Two Types of Periwinkle
The common name periwinkle is applied to plants from two separate genera within the Apocynaceae family, the dogbane family. The first group is the Vinca genus, which includes the well-known Lesser Periwinkle (Vinca minor) and Greater Periwinkle (Vinca major). These plants are native to Europe and are characterized by trailing stems and glossy, dark-green leaves. Their flowers are typically solitary, five-petaled, and appear in shades of blue, purple, or white.
The second plant is Catharanthus roseus, known as Madagascar Periwinkle or annual vinca. Unlike Vinca species, Catharanthus has an upright, bushy growth habit and produces flowers in a wider array of colors, including pinks, reds, and bi-colors, often with a contrasting central eye. Although they share the common name, their primary uses in the garden differ significantly due to their cold tolerances.
Vinca The Perennial Groundcover
The Vinca species are the true perennial periwinkles, prized as broadleaf evergreen groundcovers in temperate climates. Vinca minor, the Lesser Periwinkle, is highly cold-tolerant, reliably surviving winter in USDA Hardiness Zones 4 through 9. This species forms a low, dense mat, typically reaching only 3 to 6 inches in height, and is valued for its ability to hold soil on slopes and thrive in shady areas.
The plant spreads aggressively through long, flexible stems called stolons, which root easily wherever they touch the soil. This rooting habit allows the plant to continually expand its territory. The evergreen foliage provides year-round color, and the plant survives freezing temperatures, regrowing its blue or violet flowers each spring.
Vinca major, the Greater Periwinkle, is slightly less cold-hardy, thriving as a perennial in Zones 7 through 11. It is a more vigorous and larger species, with leaves up to three inches long, and can grow up to a foot high. Due to their aggressive, self-rooting spread, both species can become invasive in favorable climates, rapidly outcompeting other plants. Vinca is often chosen for low-maintenance spots where a consistent groundcover is desired.
Madagascar Periwinkle The Annual Bedding Plant
Catharanthus roseus, the Madagascar Periwinkle, is botanically classified as a tender perennial subshrub. Native to tropical regions, it can only survive year-round in USDA Zones 9 through 11. Outside of these climates, the plant cannot withstand the first hard frost and dies back completely, which is why it is treated as a seasonal annual bedding plant.
This type of periwinkle is favored for its upright, bushy growth habit, typically mounding to a height of 8 to 18 inches, making it ideal for containers and flower beds. It is a heat-loving plant, demanding full sun and thriving in the heat of summer, conditions where Vinca would often struggle. The plant is valued for its prolific and continuous flowering, producing blooms from late spring until the first autumn frost. Its excellent heat and drought tolerance, once established, make it a reliable source of color in sunny, dry locations.