Ceratotheca triloba ( Bernh.) Hook.f.

Family: Pedaliaceae
Common Names:
Wild foxglove; Vingerhoedblom; ludvonca (Sw); udonqa (Sw,Z); undoncalwabathwa, udonqabathwa (Z)

Ceratotheca triloba

Flowering during the warm summer and into autumn, this tall, elegant annual adds a cool and lush feeling to the garden. In nature they are commonly found in the summer rainfall areas of South Africa, especially the grasslands. Opportunistic annuals, they germinate best in disturbed areas like roadsides where they manage to grow, flower and seed before the onset of the dry, frosty winter.

The wild foxglove varies in height, depending on the amount of water it receives during the summer. In the garden with regular watering they grow 1,5 - 2 metres tall. Some plants become quite bushy while others remain single stemmed. The soft, green leaves are about 50mm long and divided into 3 lobes with a bluntly serrated margin. The leaves are carried on long thin stalks up the stems. Plants with pink flowers usually have dark red stems while white flowering plants have yellow-green stems.

The beautiful white or mauve foxglove-like flowers are carried in pairs up the stems in tall, sparsely flowered spikes. Unfortunately the promise of an overwhelming display is never fulfilled as only two or three flowers on a stem open at a time. The bottom flowers open first and form fruits while new buds are still developing at the tip of the stem. Each flower is about 50 mm long with 5 lobes, the bottom lobe longer than the others and streaked with delicate lines running into the throat.

When in flower they create quite a buzz as a favourite of the carpenter and honey-bees. In nature the wild foxglove flowers throughout summer but at Kirstenbosch the best display is during the late summer months (Feb-March). The small black seeds are formed in the 30 mm long fruits which have two very prominent horns at their tips. Within a few weeks of flowering the green fruits turn brown and dry, splitting open to release the flat, pear shaped seeds. The leaves, stems and flowers are covered in fine white hairs. The plants are slightly sticky and when crushed give off a strong unpleasant smell. The flowers last for a few days in the vase.

Growing Ceratotheca triloba

In the garden these annuals prefer rich, well-drained soils in full sun or semi-shade. The wild foxglove can survive with very little water, but to grow tall and lush, they need plenty of water throughout the summer. For the best display, plant them close together in large groups. They will seed themselves freely if left to go to seed.

Propagate the wild foxglove by seed sown during spring or early summer (Sept - Nov). Sow the seed evenly and not too thickly, in seed trays filled with a well-drained medium. Cover the seeds with a thin layer of white sand or fine milled bark, water well and place the tray in light shade. Germination is usually very good, but the young seedlings are often a bit slow to grow initially. They respond very well to feeding with organic fertiliser like Seagro or Humac as an initial boost. The seedlings can be planted into the garden as soon as they are big enough to handle, usually about 6-8 weeks after sowing.

This is the only species of Ceratotheca that is found in South Africa. Ceratotheca means having horned capsules, from the Greek kerato-, horned and theke, a case. The species name triloba means three-lobed (Latin), alluding to the leaves. Cerathotheca triloba is used in traditional medicine to treat painful menstruation, stomach cramps, nausea, fever and diarrhoea.

Liesl van der Walt
February 2001

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