Culture
Winter hardy to USDA Zones 9-12. Relatively easy to grow from seed. Needs a support structure on which to grow. Performs best in moist, fertile, well-drained soils in full sun. Once this vine has matured to cover the area it is meant to cover, cut back the leaves and tendrils to trigger the onset of significant flowering. This vine can aggressively self-seed in warm tropical areas. It may be grown in pots in northern climates which are brought indoors for overwintering to a sunny window. May be grown as an annual.
Noteworthy Characteristics
Vigna caracalla, commonly called corkscrew vine, corkscrew flower or snail flower, is a rapid-growing twining perennial vine in the pea family that is native to tropical areas of Central and South America. It is evergreen in frost free climates. It is noted for producing an ornamentally attractive July to October bloom of white and lilac-purple (sometimes marked with yellow and cream) spirally twisted flowers (each to 2” long) on erect racemes to 12” long. Flowers curl in a manner somewhat reminiscent of a snail’s shell. Vines are clad with 3-palmate green leaves (each leaf having three leaflets to 3-5” long). This vine typically matures to 12-20’ (occasionally to 30’). Each flower has a unique structure consisting of a broad-oval backward-curled upper petal (the standard) plus two coiled, fused and elongated central petals (the keel) and two side petals (the wings). Flowers are highly fragrant. Blooms occur mid-summer to frost. Flowers are followed by slender, dangling, bean-like pods (6-7” long and 1” wide) which contain rounded brown seeds. Flowers are mostly pollinated by ants.
Corkscrew vine has naturalized, sometimes spreading aggressively, in parts of California.
Flowers spirally twist on the vine in a manner suggestive of a corkscrew, hence the common name of corkscrew vine.
Genus name honors Dominicus Vigna (1581-1647), Italian scientist/professor and botanist.
Specific epithet honors Caracas, Venezuela which is part of the native habitat of this plant.
Problems
No significant insect or disease problems.
Uses
Where winter hardy, grow as cover for trellis, arbor, fence or wall. Where not winter hardy, grow in a container that is brought indoors to a sunny window in winter.