Thunbergia erecta is a summer-flowering shrub with bright purple-blue flowers. The 2-inch wide, tubular blooms have a yellow throat and hang below the stem of the plant. Sporadic flowering may occur at other times of the year.
This species is native to tropical Africa and is recommended for USDA Zones 10B-11. Mine has been happily growing in Zone 9B without protection for more than 20 years. It has also never been watered or fertilized in that time, so although the plant looks delicate, it seems to be very durable.
Thunbergia erecta grows best in full to part sun and reaches a height and spread of 4-6 feet.
It is also sometimes known as Bush Clock Vine or King's Mantle.