Thunbergia alata, commonly called black-eyed Susan vine, is a herbaceous perennial climbing plant species in the family Acanthaceae. It is native to Eastern Africa, and has been naturalized in other parts of the world.
It is grown as an ornamental plant in gardens and in hanging baskets. The name 'Black-eyed Susan' is thought to have come from a character that figures in many traditional ballads and songs. In the Ballad of Black-eyed Susan by John Gay, Susan goes aboard a ship in-dock to ask the sailors where her lover Sweet William has gone. Black-eyed Susan is also a name given to other species of flowers in the genus Rudbeckia.
The plant is originally from East Africa, and has almost a world distribution including tropical and subtropical areas like China, eastern Australia, Hawaii, Southern US in the states of Texas and Florida, Colombia, Puerto Rico, Mexico, South Africa, Portugal, Japan, New Zealand, Cerrado vegetation of Brazil, Argentina, Madagascar, India, Thailand and Philippines, among others.
It is used all around the world as a garden plant, but has managed to "escape" to the wilderness, naturalizing in tropical and temperate forests. It has been widely reported as Invasive species, especially in the Caribbean and Pacific islands, from Mexico to Colombia, and in Japan, due to the fast growing of the plant; the ease of wild pollination during sporadic flowering times; its vine-growing strategies that strangle or create shadow on other plants; its difficulty to eradicate by hand (as it leaves underground rhizomes that rapidly grow back); its lack of usual predators in non native regions; plus, people who are unaware of its harmful nature to other plants in the wilderness tend to admire its beauty and might opt not to remove it.
