In this educative and inspiring column, Girija Viraraghavan discusses, in detail, the flowers found in the wild and in the gardens of many homes in Kodaikanal. This series will feature a number of her articles, each describing a flowering species found in our hills. These pieces, edited and adapted for today, first appeared in The Friendly Post, a Kodai newsletter that was published from 2003 to 2011.
Remember that old song ‘Pretty little black-eyed Susy’? Well, ‘black-eyed Susy’ or ‘Susan’ has been the stuff of traditional ballads and songs, originally attributed to a John Gay, about a girl searching for her lost sailor. Somehow the name has been transposed to this plant, perhaps because it’s a rich golden orange with a black centre, reminiscent of a pretty tanned girl with sparkling black eyes.
Belonging to the botanical plant family Acanthaceae, the genus name of this particular plant is Thunbergia, and its specific name is alata. In much of the warmer world, Thunbergia alata, or ‘black-eyed Susan’, is well known as a fast-growing, long-flowering, friendly, soft creeper. It is a herbaceous perennial climbing plant, native to Eastern Africa but has been naturalized in other parts of the world like Brazil, Hawaii, southern states of the US, and Australia, and of course, India.
It is grown as an ornamental plant in gardens and in hanging baskets. It is not fussy about soil, needs only moderate water, doesn’t go rampant, is mostly evergreen, and covers ugly places beautifully. It has a vine-like habit and can grow to 6-8 feet (1.8-2.4m), less as a container plant. It has twining stems with heart or arrow shaped leaves. It favors sun to partial shade. The flowers are typically a warm orange with a characteristic dark spot in the center, though there are varieties in red, red-orange, white, pale yellow and bright yellow, some without the dark chocolate purple center.
The fruit is like a bird’s head with a spherical base and a long ‘beak’. This plant flowers all summer, but can continue all year in warmer areas.
Thunbergia, named in 1780 by Retzius, honors Carl Peter Thunberg (1743-1828), a Swedish botanist, doctor, explorer and author who was perhaps the greatest pupil of Linnaeus. Thunberg spent three years collecting at the Cape of Good Hope, finding about 300 new plant species. He was so keen a collector that when Japan was closed to all Europeans except the Dutch, he joined the East India Company as a surgeon so he could collect there. Seed of Thunbergia alata, named by Bojer, a German botanist, was sent from Mauritius to England where it was first described by Sims in 1825. (Surprisingly the plant had cream-coloured, not the common orange flowers.) The species name is from the Latin ‘alatus’, meaning ‘winged’. It refers to the winged petioles but it could also allude to the seeds that have projections looking rather like wings.
Thunbergia alata is one of some 90 old world species. Other species in cultivation are T grandiflora Roxb, the blue-flowered Bengal clock vine, from India, and T gregorii, the golden glory vine, with strong orange flowers but no dark ‘eye’. T mysorensis has the most beautiful flowers, which hang down in a most elegant manner. A pandal of T mysorensis is a breathtaking sight.
Used mainly as an ornamental plant, Thunbergia alata makes a good screen when used to cover unsightly dead trees or walls. It needs some support, as it cannot cling. Use fences, trellises, arches, arbors and pillars or a lightly shading tree (pergolas would probably be too big) to assist it. Alternatively, plant this creeper in groups as ground cover, or on a bank or terraces where it can trail downwards.
Black-eyed Susan is used as a vegetable or stock feed. Medicinally it is used for skin problems, cellulitis, back and joint pains, eye inflammation, piles and rectal cancer. Gall sickness and some ear problems in cattle are also treated with this plant. Some people can get contact dermatitis from it.
It is a charming and cheerful, trouble free plant which needs no looking after except pruning now and then, when it takes over an area or a tree. Otherwise it just needs to be enjoyed.