Thunbergia alata Bojer ex Sims
Black-eyed Susan Vine
Bloom Time: Summer
Thunbergia alata is a perennial climbing plant with many twining stems. It grows up to 8 feet (2.4 m) tall. Leaves are heart or arrow-shaped, softly hairy, and sometimes toothed. Flowers have five petals and appear throughout the summer but can continue all year in warmer areas. Typically they are warm orange with a characteristic dark spot in the center.
USDA hardiness zone 9a to 11b: from 20 °F (−6.7 °C) to 50 °F (+10 °C).
How to Grow and Care
Plant Thunbergia seedlings outdoors after all frost danger passes, or start your own seeds indoors six weeks before the last expected frost. With proper care, the vines remain in bloom from midsummer until fall frost.
Spread 2 inches (5 cm) of compost over a well-drained garden bed that receives full morning sunlight and light afternoon shade. Site the bed near a trellis, fence, or similar 5 to 8 foot (1.5 to 3.4 m) tall support. Work the compost into the top 8 inches (20 cm) of soil.
Plant the seedlings along the base of the support. Space the plants 12 inches (30 cm) apart. Plant the seedlings at the same depth they were growing at previously.
Water Thunbergia deeply once a week, providing approximately 1 inch (2.5 cm) of water during irrigation or enough to keep the top 6 inches (15 cm) of soil evenly moist. The plants require less irrigation during rainy weather, and they may require twice weekly irrigation during times of dry, hot weather.
See more at How to Grow and Care for Thunbergia.
This species is native to eastern Africa and has been naturalized in other parts of the world.
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