Cape Primrose


This little, indigenous forest plant, Streptocarpus, was first discovered in Knysna in the 1800s and also occurs naturally in the Drakensberg is one of our most adaptable and freely flowering garden shade plants. Perhaps the name has something to do with it, but it’s hard to know why it is not more popular.

Streptocarpus grower Leoné Williams speculates that the plant’s exotic appearance creates the impression that it is fussy and difficult to grow. Nothing could be further from the truth, she says. Streptocarpus grows easily in dappled sunlight as well as in full shade, as long as there is good light. Too much sun burns the leaves and fades the flowers.

It is also remarkably free from pests and diseases and sails through cold winters. Some varieties may die back but they sprout again in spring. It does best when planted in slightly acid, light and well drained soil, so it’s a good idea to dig in organics like peanut shells, peat, pine needles or bark compost before planting.

Plants grown indoors should receive plenty of bright light but no direct sunshine, she advises. Plant in fairly shallow, small pots (10cm diameter) and use acid compost or regular potting soil with some peat mixed in as a potting medium.

Regular watering is essential but be careful not to over water because this can cause root rot to develop. Either too much water or too little water can cause wilting leaves. If the plants are in a pot, make sure the potting soil is dry before watering and water less often in winter.

Streptocarpus benefits from a monthly dose of potassium rich food. The simplest is two teaspoons of Epsom salts per 10 litres of water, once a month or liquid fertiliser like Nitrosol, Margaret Roberts Supercharger or Multi-feed. To encourage the plant to produce more flowers, cut off dead flowers. Plants that produce more leaves at the expense of flowers may not be getting enough light or may be receiving too much fertiliser.

Streptocarpus propagates easily although the method is quite unusual. Simply take a fresh young leaf from the centre of the plant and place the cut end in a mixture of equal parts of compost and vermiculite or perlite. Cover the pot with a plastic bag and put it in a shaded place that is well lit. Keep the medium damp, but not sodden, and within a month the cutting should have rooted and a new plant will grow from the base.

There are many different hybrid varieties, ranging in colour from all shades of blue (the most common colour) through to maroon, pink and white. Gardeners wanting to establish an indigenous wooded garden can combine them with Plectranthus and indigenous ferns because they have the same kind of soil, moisture and light requirements.

The Gardener