Thunbergia alata (Black-eyed Susan) - An attractive and cheerful evergreen vine that sprawls along the ground and clambers up on anything that will support it. The twining stems will reach 6-8 feet and are covered with triangular-shaped leaves that have winged petioles and nearly year-round, but strongest from summer through fall, orange tubular flowers that have dark purple, almost black throats.
This plant is often treated as an annual in areas where it is killed by temperatures much below 28° F but in near frost-free zones it is an evergreen vine. Plant in sun or part shade where it is not fussy about soil types and can be water regularly to only occasionally. A nice plant for covering a low chain link fence or for covering unsightly items in the garden. It is considered attractive enough to be honored with a set of South African postage stamps.
Thunbergia alata comes from forest margins in tropical Africa southwards through the eastern parts of Limpopo, Mpumalanga and Swaziland to KwaZulu-Natal and Eastern Cape in South Africa. Though similar to its more tropical African relative, the Orange Clock Vine, Thunbergia gregorii, this plant is easily disguisable by the dark-centered eye of the flower and the winged petioles. The name for the genus honors the Swedish naturalist Carl Peter Thunberg (1743-1828) who was a student of Linnaeus and spent several years botanizing the Cape of Good Hope. The specific epithet is from the Latin word 'alatus' meaning "winged" in reference to the flattened wing like growth on the leaf petioles. This plant is well known in cultivation with several flower color variants such as the yellow form we grow as Thunbergia alata 'Yellow'. This species has long been in cultivation in California and was introduced here by William Walker at this Golden Gate Nursery in 1854.
The information about Thunbergia alata displayed on this web page is based on our research conducted in the nursery's horticultural library and from reliable online resources. We also include observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments we receive from others and welcome hearing from anyone with additional information, particularly if they can share cultural information that would aid others in growing this plant. |