Periwinkle Periwinkle is also called vinca or myrtle. Of the 12 species of periwinkle, two are popular ground- covers. All species have opposite leaves and single flowers. Oblong to ovate leaves are opposite, simple, to 2 inches long, glossy, with a short petiole. They exude a milky juice when broken.
Flowers are purple, blue or white depending on the cultivar.
Plants bloom in April and sometimes again in the fall. Vinca minor grows about 6 inches tall, spreading in all directions by sending out long trailing and rooting shoots, which make new plants. Vinca major or large periwinkle is a larger, more aggressive species than V. minor . Leaves are up to 3 inches long. The blue, funnel-shaped flowers are 1 to 2 inches in diameter.