Bengal Clock Vine (Thunbergia grandiflora): Sky-Blue Trumpets on a Vigorous Climber

Bengal clock vine (Thunbergia grandiflora), also called blue sky vine, is a rampant, woody vine that can climb 30 feet or more, covering structures with large, heart-shaped leaves and pendulous clusters of 3-inch, sky-blue, trumpet-shaped flowers with pale yellow throats. It blooms heavily in warm months.

Growth

Very vigorous—requires strong support and regular pruning to contain. In frost-free zones (10–11), it is evergreen and blooms year-round; in zone 9, it may die back but returns. Can be grown as an annual in cooler areas.

Culture

Full sun to part shade; rich, moist, well-drained soil. Water regularly. Feed monthly. Prune aggressively after flowering.

Taxonomy

• Family: Acanthaceae
• Genus: Thunbergia
• Species: grandiflora