The vinca is an evergreen perennial with a trailing habit, best used for ground covers and rough slopes. Also known as periwinkle or myrtle, vinca is extremely invasive in sheltered or forested areas. Vinca major has dark green, glossy, oval foliage, on short branches, with small lavender-blue flowers. Vinca minor has foliage more oblong with shorter stalks, and has a wider range of shades for blooms, including blue, white, double blue and deep blue. White-variegated foliage is also common in both varieties.
Vinca has long, trailing stems that root as they grow. They mound up to 6 to 12 inches and grow up to 2 feet in height.
Vinca grows well in shaded areas. Vinca major tolerates some sun if watered generously. (p.519)
Vinca major grows in zones 5 to 24. Vinca minor grows in all zones, but does not tolerate sunny areas in zones 1, 2, 3, 7 and 10 to 13.
Vinca requires moderate moisture in shady areas. In areas that receive more sun, more regular watering is required.
Vinca rosea, or Catharanthus roseus, is a perennial, but is often grown as an annual. It's a bushy plant, with glossy foliage and flower colors ranging from pure white, to white with rose, to blush pink, to bright rose. It is best grown in full sun or partial shade, and prefers drier soils. Vinca rosea is self-seeding.