Many people encounter periwinkle in gardens and natural settings, often wondering about its exact botanical nature. This popular plant prompts questions regarding its classification. This article aims to clarify whether periwinkle is indeed a flower, exploring its identity within the plant kingdom and distinguishing between its commonly recognized forms.
Botanical Identity of Periwinkle
Periwinkle is a flowering plant. It belongs to the Apocynaceae family, often referred to as the dogbane family, which includes a diverse range of flowering species. Periwinkle species are classified as evergreen subshrubs or herbaceous perennials, meaning they can live for more than two years and retain their foliage year-round.
Distinguishing Periwinkle Species
Confusion arises because the name periwinkle refers to two distinct genera: Vinca and Catharanthus. The most common species are Vinca minor (common or lesser periwinkle) and Catharanthus roseus (Madagascar periwinkle). Vinca minor is native to Europe, northwestern Africa, and southwestern Asia, growing as an evergreen groundcover. It spreads by trailing stems that root where they touch the ground, forming dense mats.
Catharanthus roseus originates from Madagascar and is cultivated as an ornamental bedding plant, often treated as an annual in warmer climates. While both produce flowers, their growth habits and uses differ significantly. Vinca minor is used for groundcover and erosion control, thriving in shaded or partially shaded areas. Catharanthus roseus is prized for its continuous blooms and is seen in garden beds, borders, and containers, preferring full sun.
Key Characteristics and Growth
Periwinkle plants display distinct physical attributes in their flowers, leaves, and growth patterns. The flowers of both Vinca and Catharanthus species have five petals, often appearing star-shaped or pinwheel-like. Flower colors span shades of blue, purple, and white for Vinca minor, with some cultivars also showing pink or red-violet hues. Catharanthus roseus offers a broader color palette, including pink, rose, red, white, and bi-colored patterns, often with a contrasting “eye” or throat.
The leaves of periwinkle species are glossy, dark green, and arranged oppositely on the stem. Vinca minor leaves are oblong to ovate, measuring about 0.5 to 2 inches long, and maintain their evergreen nature, providing year-round interest. Catharanthus roseus leaves are elliptic or oval, ranging from 1 to 3.5 inches long, and also glossy green. Vinca minor is known for its low-growing, spreading habit, reaching 3 to 6 inches in height, while Catharanthus roseus can grow more upright, forming bushy mounds 6 to 18 inches tall.