Culture
Winter hardy to USDA Zones 10-11. Best grown in moist, fertile, well-drained soils in full sun. In St. Louis, grow in containers which must be overwintered indoors in a greenhouse or sun room. May be grown from seed, but will not bloom the first year.
Noteworthy Characteristics
Petrea volubilis, commonly called Queen’s wreath or purple wreath. is native to the West Indies and from Mexico to Panama. It is a fast-growing, twining, woody vine or rounded shrub that produces wisteria-like erect to drooping axillary foot-long racemes of star-like purple flowers (15-30 flowers per raceme) in late spring to early summer. The showy parts of each flower are the 5 narrow petal-like calyx lobes which persist long after the darker purple corollas drop. Oblong-elliptic, dark green leaves (4-9” long) are rough above, hence the sometimes common name of sandpaper vine. In its native habitat, this plant can grow rapidly to 25-40’, but in cultivation is more often seen as a much smaller vine or trained as an espalier or standard.
Genus name honors Lord Robert James Petre (1713-1743), English patron of botany and horticulture.
Specific epithet means twining.
Problems
No serious insect or disease problems. Susceptible to mold. Watch for scale and mealybugs. Spider mites are less frequent visitors.
Uses
Spectacular flowering vine for pergolas, fences, trellises or porches. Train as a standard. Also effective in hanging baskets.