A most rapidly growing, most floriferous, greenhouse climber Thunbergia alata, Black-eyed Susan was introduced at the start of Victoria’s reign. Many others in this genus also became popular in Hot-houses of the 19th century for their magnificent displays, and because most were relatively fast growing just wanting to bloom .
Black-eyed Susan was ‘first’ found in the East Indies though had already travelled there from it’s home in tropical Africa. More species were discovered in Madagascar and India, and are still widely grown, though T. alata is the tougher and so has remained by far the most popular.
Black-eyed Susan has even moved out to the open garden for the summer where its ease and speed have made it popular as a half hardy climber i.e. it has to be started indoors in the warm then planted out after the garden warms up for summer.
For sheer non-stop flowering and rapid covering power this is unbeatable, either climbing, or trailing, it can even be grown to cascade from hanging baskets. Indeed the only rival’s Bindweed, indeed it’s fortunate Black-eyed Susan is not hardy as it would likely be a pernicious weed.
Once you’ve found how rewarding Black-eyed Susan is you’ll grow it every year. Theoretically a short lived perennial you might prolong old plants, and you can easily over-winter young plants taken from cuttings in late summer. But fresh seedling plants perform as well if not better and with less risk of over-wintering pests or diseases from all the usual suspects.
Start from seed, there’s choice of colour; reds, yellows and white, though the original orangey yellow with a brown eye is hard to beat. Any free draining compost will serve though better enriched with leaf-mould which this genus love. Feed and water heavily, and provide sticks early on.
Other species are also worth growing in larger, warmer, greenhouses. T. coccinea with red flowers and T. grandiflora with large blooms are both lovely but especially desirable is T. fragrans which as its name suggest has beautifully perfumed white flowers, and reaches 20 foot the first season!
Oh yes, oddly often mis-thought an ‘American’ plant in the UK in the USA Black-eyed Susan may also refer to Rudbeckia hirta, a different flower of similar appearance, and apparently in Texas slang to a revolver!