Thunbergia alata 'Yellow' (Yellow Black-Eyed Susan Vine) - 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, yellow 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 can be a perennial. This plant was severely damaged except where protected under eaves at 28° F in our January 2013 freeze. Plant in sun or part shade and water regularly to occasionally.
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. The species plant, which we also grow and list as Thunbergia alatais well known in cultivation and has been grown in California since 1854 but there are several flower color variants such as this yellow form that are newer to cultivation. We have grown this plant or another very similar yellow cultivar known as 'Lemon Star' since 2004.
The information about Thunbergia alata 'Lemon Star' 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. |