Black-eyed Susan

Edibility: 

In East Africa, it is used as a vegetable or stock feed.

Toxicity: 

Some people can get contact dermatitis from it.

Uses:

• Ornamental: Widely used as a fast-growing, long-flowering ornamental climber.

• Screening: Excellent for covering unsightly walls, fences, dead trees, trellises, arches, arbours, and pillars. It needs support as it cannot cling.

• Groundcover: Can be planted in groups as a groundcover, or on banks and terraces where it can trail downwards.

• Containers: Suitable for hanging baskets.

• Medicinal: Used in traditional medicine for skin problems, cellulitis, back and joint pains, eye inflammation, piles, and rectal cancer. Also used for gall sickness and some ear problems in cattle.

Ecology:

• Probably pollinated by bees and other insects.

• Flowers reflect ultraviolet (UV) light in patterns visible to insects but not to humans, guiding pollinators.

• Butterflies, such as the Eyed Pansy (Junonia ovithya), and moths visit the plant to lay eggs, attracting insectivorous birds.

• Small birds often nest in the thickly tangled stems.

Distribution and habitat:

• Found from tropical Africa southwards through the eastern parts of South Africa (Limpopo, Mpumalanga, KwaZulu-Natal, and Eastern Cape).

• Usually found on forest margins, but can also occur in drier, open areas.

• Sometimes seen along roads near settlements.

• It has become naturalised in Asia and Malesia and is considered invasive in Hawaii and Australia in frost-free regions.

Derivation of name:

• The genus name Thunbergia honours Carl Peter Thunberg, a Swedish botanist and explorer who made significant contributions to the study of Southern African flora.

• The species name alata is from Latin, meaning 'winged', which refers to the winged petioles of its leaves, but could also refer to the winged projections on its seeds.

Historical aspects: 

Has been widely cultivated for a long time, making its exact natural distribution unclear. It has even been honoured in a standard set of South African postage stamps.

Interesting facts:

• This plant is so loved, it even made it onto a set of South African postage stamps! How cool is that?

• Its "black eye" isn't just for show; it's a special UV pattern that only insects can see, guiding them to the nectar. It's like a secret road map for pollinators!

• Watch out for its "bird's head" fruits – they have a secret popping mechanism! When they're dry and ready, they'll burst open with an audible snap to shoot their seeds far and wide.

Growing tips:

• Seed germinates easily in a damp mixture of fine, humus-rich soil with some sand.

• Cover seeds with a thin layer of soil and keep moist. Dark conditions can help germination.

• Mature plants may have seedlings underneath that can be transplanted.

• Plant in light soil rich in humus with good drainage.

• Water well initially, then moderately throughout the year, especially in summer.

• Add compost as a mulch 2-3 times per summer.

• Can be treated as an annual in very cold areas as it may die back with frost but can self-seed.

• Prune back quite hard once a year to keep it tidy and encourage more flowers.