The question of whether Vinca requires full sun or shade is complicated because the common name “Vinca” is used for two very different plants with opposing light requirements. The confusion arises from a botanical name change, but the practical difference is between a shade-loving perennial groundcover and a sun-demanding flowering annual. This guide resolves that common confusion by detailing the specific light and cultural needs for each species.
Clarifying the Two Plants Called Vinca
The name Vinca is commonly applied to two distinct groups of plants: the true Periwinkles and the flowering annuals. The true Periwinkles belong to the genus Vinca (Vinca minor and Vinca major), often called Lesser Periwinkle or Creeping Myrtle. These plants are perennials, primarily used as evergreen groundcovers due to their low, trailing habit.
The second plant, often called Annual Vinca or Madagascar Periwinkle, is botanically known as Catharanthus roseus. This plant is a warm-weather tender perennial most commonly grown as a summer annual bedding plant in cooler climates. It has an upright, bushy growth habit, typically reaching 6 to 18 inches in height, flowering continuously from summer until the first frost. The key difference is that Vinca groundcovers produce small, blue or purple flowers in spring, while Catharanthus roseus is a bushy plant with pink, white, or red blooms that flowers all summer.
Specific Light Requirements for Each Type
The light requirements for the two plants called Vinca are opposite, making correct identification important.
The perennial groundcover, Vinca minor, prefers partial to full shade for optimal foliage health. While adaptable to full sun in cooler regions, intense afternoon sun in hot climates can scorch or yellow the leaves. The best environment receives morning sun or filtered light, which helps maintain consistent moisture and prevents leaf burn.
In contrast, the annual bedding plant, Catharanthus roseus, is a sun-loving species that demands high light levels to flower profusely. This plant requires a minimum of six hours of direct sunlight daily for robust growth and continuous blooming. In too much shade, the plant becomes “leggy,” stretching its stems, and flowering is inhibited, resulting in sparse foliage and few blossoms.
Companion Care Factors
Successful growth for both types of Vinca depends on proper soil and drainage, as both are susceptible to root problems in overly wet conditions.
Soil and Drainage
The annual Catharanthus roseus is particularly prone to root rot and fungal diseases if the soil remains soggy, reflecting its adaptation to hot and dry slopes. Well-draining soil is essential for both the perennial groundcover and the annual bedding plant.
Watering
Watering practices must be adjusted for the specific plant and its light exposure. The perennial Vinca minor is drought-tolerant once established, but in full sun, it requires more consistent watering to prevent scorching. The annual Catharanthus roseus also tolerates drought once established, but thrives best with regular weekly watering, ensuring the soil dries out between sessions.
Maintenance
Routine maintenance varies significantly due to the plants’ differing growth habits. The annual Catharanthus roseus requires minimal pruning, though pinching back stems encourages a bushier, more compact shape. Conversely, the perennial Vinca minor is a vigorous groundcover that spreads rapidly through rooting stems and may need to be cut back hard in early spring to restrict its growth.