The term “Vinca” causes confusion because it refers to two completely different plants: a long-lived perennial groundcover and a vibrant annual bedding plant. The distinction is based on their botanical family and climate adaptation. Understanding which plant is being discussed is essential to determine if it is a perennial or an annual.
Resolving the Naming Confusion
The confusion stems from a historical misclassification and the use of the common name “periwinkle” for two different genera. The true perennial plants belong to the genus Vinca, which includes species like Vinca minor and Vinca major. These are genuine perennials, often called creeping myrtle, that survive year after year. The second plant, usually sold as “Annual Vinca,” is Catharanthus roseus, also known as Madagascar Periwinkle. Although botanically a tropical perennial, it is treated as an annual in most regions because it cannot survive freezing temperatures.
Characteristics of Perennial Vinca
True perennial Vincas (Vinca minor and Vinca major) function as broadleaf evergreen groundcovers. Vinca minor is the more cold-hardy, surviving winter in USDA Hardiness Zones 4 through 9. This species forms a dense, low-growing mat, typically 3 to 6 inches tall, making it effective for erosion control.
These creeping plants spread via trailing stems that root at the nodes, allowing them to cover large areas. Perennial Vinca prefers partial to full shade, making it a popular choice for planting beneath trees where turfgrass struggles. It has glossy, dark green foliage that provides year-round color. It produces small, star-shaped flowers, usually lilac or blue, primarily in the spring.
Characteristics of Annual Vinca (Madagascar Periwinkle)
Annual Vinca (Catharanthus roseus) is cultivated for its continuous blooming season from late spring until the first hard frost. Distinct from perennial varieties, it forms an upright, bushy mound, typically 8 to 18 inches tall. The flowers are larger, featuring five overlapping petals in colors including white, pink, red, and rose, often with a contrasting center.
While technically a perennial in tropical environments (Hardiness Zones 9-11), it is sensitive to cold and dies in temperate climates. This species prefers full sun and possesses excellent tolerance for heat and drought—conditions opposite those preferred by perennial Vinca. Its ability to withstand intense mid-summer heat makes it a reliable bedding plant for sunny areas and containers.
Practical Care Based on Classification
The difference in lifecycle dictates the approach to care. Perennial Vinca requires minimal maintenance once established, primarily needing pruning to control its aggressive, spreading habit. As a cold-tolerant perennial, it does not need replanting or bringing indoors for winter. It grows best in moist, well-drained soil in shaded or partially shaded locations.
Annual Vinca (Catharanthus roseus) requires different treatment because it is grown for prolific summer bloom and cannot survive winter. This type needs warm soil and full sun. Although drought-tolerant, consistent watering supports continuous flowering. It is considered self-cleaning, so faded flowers do not need removal. The plant must be discarded after the first killing frost.