Mysore Clock Vine

Thunbergia mysorensis is native to southern India, specifically the Western Ghats mountain range in the states of Karnataka and Kerala, where it grows in moist, evergreen to semi-evergreen forests on mountain slopes.

• Named after the city of Mysore (now officially Mysuru) in Karnataka state, where the plant was first collected
• The species name mysorensis means "from Mysore"
• The Western Ghats of India, the native habitat of this species, is a UNESCO World Heritage Site and one of the world's most important biodiversity hotspots
• The vine has been planted in tropical botanical gardens worldwide, where it is one of the most photographed and admired plants
• In its native India, the plant is sometimes found in traditional gardens near temples and palaces
• The genus Thunbergia honors Carl Peter Thunberg (1743–1828), the Swedish botanist
• The "Clock Vine" common name refers to the twisted buds, though T. mysorensis flowers are larger and more dramatically displayed than most other Thunbergia species
• The plant has received the Royal Horticultural Society's Award of Garden Merit for its extraordinary floral display
• Relatively uncommon in cultivation compared to T. alata and T. grandiflora, due to its large size and tropical requirements

Mysore Clock Vine is a vigorous evergreen woody vine climbing by twining stems to heights of 6–10+ m, creating a massive curtain of foliage and hanging flower racemes.

Stems: Stout, woody, quadrangular (square in cross-section), twining vigorously around supports. Young stems are green; mature stems become thick and woody, capable of supporting the weight of massive flower racemes.

Leaves: Opposite, ovate to lanceolate, 10–20 cm long and 5–10 cm wide, dark green, slightly hairy, with entire or slightly toothed margins and a pointed tip. Leaves are arranged in flat, overlapping sprays along the stems.

Flowers: The supreme feature — produced in extraordinary, pendulous, one-sided racemes that can reach 30–100 cm in length, each bearing 30–50+ individual flowers. Individual flowers are 4–5 cm long, tubular with a broad, two-lipped mouth. The outside of the tube is bright brick-red to crimson, while the inside (the open mouth) is brilliant golden-yellow — creating a stunning bicolored effect. The flowers hang pendulously like a string of exotic jewels, and the overall effect of multiple racemes cascading from the vine is breathtaking. Long, exerted stamens add to the exotic appearance. Blooms primarily in spring and early summer in the tropics.

Fruit: Beaked capsules. Rarely produced in cultivation.

Roots: Extensive, fibrous root system.

Mysore Clock Vine grows naturally in the moist, evergreen forests of the Western Ghats in southern India, where it climbs through the canopy on forest margins and along streams in warm, humid, tropical montane conditions.

• Requires warm, humid, tropical to frost-free subtropical conditions
• Thrives in partial shade to full sun — best with some afternoon shade in the hottest tropical conditions
• Prefers moist, fertile, well-drained soils rich in organic matter
• The long, pendulous flower racemes are an adaptation for pollination by sunbirds and hummingbirds, which hover in front of the hanging flowers to feed on nectar
• The red and yellow coloration is a classic bird-pollination syndrome — red attracts birds, and the contrast with yellow acts as a nectar guide
• The massive flower display requires a substantial plant to support it — young or small plants produce fewer and shorter racemes
• Needs a strong, permanent support structure — the combined weight of foliage and flower racemes can be considerable
• Best displayed on a high pergola, arbor, or strong horizontal wires where the hanging racemes can cascade freely
• Generally pest-free in good cultural conditions
• Not considered invasive, as it rarely sets seed in cultivation

Mysore Clock Vine is a large, dramatic tropical vine that needs substantial space and support to display its spectacular flowers properly.

Site Selection: Full sun to partial shade. Plant where the hanging flower racemes can cascade freely — on a high pergola, arbor, over an entryway, or on strong horizontal wires at least 3 m above ground. The flowers are best viewed from below, so elevated plantings are ideal.

Soil: Fertile, moist, well-drained soil enriched with organic matter. pH 5.5–7.0.

Planting: Plant container-grown vines in spring. Space 3–5 m apart. Provide a very sturdy, permanent support — mature vines are heavy.

Container/Greenhouse: In temperate zones, grow in a large container or plant in a warm greenhouse with overhead support. The vine needs height to display its hanging flowers.

Watering: Regular, deep watering. Keep soil consistently moist during the growing season. Reduce water in winter but do not let dry out completely.

Fertilization: Feed monthly during the growing season with a balanced or bloom-boosting fertilizer.

Pruning: Prune after flowering. Remove dead wood and shorten overly long stems. Can be cut back hard if needed — regrows vigorously.

Training: Train young stems upward to the support. Once established, the vine climbs on its own.

Hardiness: USDA Zones 10–12. No frost tolerance — must be protected or grown indoors in cold climates.

Propagation: By semi-hardwood cuttings in summer with bottom heat. Can also be propagated by air layering.