The genus Thunbergia includes 100 or so species of annuals, evergreen perennials, twining climbers, and shrubs from Africa, Madagascar, and Asia. Their showy, often tropical-looking flowers are trumpet shaped with spreading lobes, blooming mainly in summer. Use in a greenhouse where not hardy or outdoors as annuals in a sheltered site. In warmer areas, grow the shrubby and perennial species in borders, and the climbers on an arch, pergola, or tree.
Noteworthy CharacteristicsShowy blue, yellow, orange, red, or white flowers with spreading lobes.
CareIn the garden, grow in moist but well-drained, fertile soil in full sun. Prune climbers in early spring. Tropical climbers need partial shade. Under glass, grow in full light with shelter from hot sun. Water freely during growth and sparingly in winter.
PropagationSow seed at 61° to 64°F in spring. Using bottom heat, insert greenwood cuttings in early summer or semi-ripe cuttings in mid- or late summer. Plants may also be layered in spring.
ProblemsIndoors, spider mites, whiteflies, and scale insects may be problems.