Streptocarpus parviflorus Hook.f.
Common names: Cape primrose, wild gloxinia (Engl.)
This is a stemless, soft herbaceous, pot plant, with clusters of white, tubular flowers showing pretty violet streaks in a pale yellow throat.
This is a clump-forming, stemless plant, with a cluster of basal leaves arranged in a rosette on a stout horizontal rhizome.
Leaves are stalkless, upright, strap-like and rough, greener above than below, with shallow toothed margins. As they get older and larger, they can become almost shaggy in appearance.
Delicate, 2–12, long flower stems, up to 250 mm long, arise from near the bottom of each leaf’s midrib. The first flower buds develop in spring lusters of up to 20 flowers per inflorescence held above the base of leaves on a flower stalk with many flowers open at the same time. White tubular flowers, sometimes suffused with pale violet, open to a 5-lobed, rounded, spreading mouth, with a yellow stripe on the floor of the corolla tube, usually with 3–7 violet streaks in the throat. Flowering time is December to March.
Fruits are spirally twisted, slender pod-like capsules, filled with masses of minute seeds.
According to the Red List of South African plants, Streptocarpus parviflorus is listed as LC (Least Concern).
Distribution and habitat
Streptocarpus parviflorus occurs naturally in forests, growing epiphytically on soil banks or on rocks faces in the Limpopo and Mpumalanga Provinces.
Derivation of name and historical aspects
There are two subspecies in this species:
- Subsp. parviflorus (=S. luteusC.B.Clarke in part)
- Subsp. soutpansbergensis Weigend & T.J.Edwards
The name Streptocarpus is derived from the Greek words, streptos, meaning ‘twisted’ and, carpus, meaning ‘fruit’, which describes the plants’ spirally twisted seed pods. The species name parviflorus is Latin for ‘with small flowers’.
Streptocarpus belongs to Gesneriaceae, the same family as do the well-known African violets and gloxinias that are grown as pot plants all over the world. This is a large family of mostly tropical and subtropical herbs, with ± 130 genera, and ± 2 900 species worldwide. There are 8 genera in Africa, with the one genus, Streptocarpus, in South Africa and has ± 51 species. The family is named after Konrad Gesner. He was a Swiss scholar, and in 1963, 30 years after his death, his name was given to this family.
Gesneriaceae are often epiphytic (growing on trees) or lithophytic (growing on rocks).
The plants can be cross-pollinated easily with other species, but in many instances are self-pollinated. The very small seed is distributed by wind.
There are a wonderful variety of easy to grow Streptocarpus hybrids in all shapes and sizes, with really striking flower colours and forms, which make very popular indoor plants.
Growing Streptocarpus parviflorus
Streptocarpus parviflorus is a plant that is seldom seen in gardens because of its unavailability in the trade.
Streptocarpus in general, are all very sensitive to direct light, and are burned easily by the sun, but flower poorly in deep shade. Light shade with good ventilation is best for growing healthy plants with plenty of flowers.
Watering streptocarpus should be done with care. It is very important that the plants should not be over-watered to prevent rotting and fungal problems. They have quite shallow root systems, as in nature they often thrive in very little soil, so allow them to get quite dry between watering. In fact, they like being allowed to wilt slightly between each watering, and they have the ability to recover very well from this. Be aware that severe wilting can be a sign of root rot caused by over-watering, so check the soil to see that this is not the case.
Avoid wetting this plant’s leaves, by watering from the base—pour water into the pot tray, so that the plant and soil can absorb what is required from there. During the warm summers when they are actively growing, the plants need regular watering, but note that most streptocarpus ‘rest’ in winter, and this slight dormancy will cause them to need very little water during this time, so be sure to reduce the amount given.
Regularly remove all dead, unhealthy, dying leaves and flowers as these encourage fungal growth, and to keep the plants looking attractive. Removing spent flowers can often stimulate a second flush of flowers.
The tips of the leaves often die off as they get older or when stressed by drought or low temperature or when over-wintering. This unattractive tip can be cut off/removed without harming the growth of the leaf, as it would naturally shed this through an abscission layer and continue with new growth from the base.
Regular feeding during the growing season with liquid foliar feeds, is recommended.
Repot once the plant’s roots appear at the bottom of the pot.
All propagation is best done in spring which is the start of the growing season, Streptocarpus can easily be grown from seed. When sowing the seeds, mix a pinch of the dust-like seeds with a small amount of sand to assist with spreading the seeds evenly. Use a well-drained, spongy medium that is not too coarse. At the Kirstenbosch National Botanical Gardens, we use equal parts peat and compost. Cover with a very thin covering of sand, keep out of direct sun, but in warmth, and water regularly with a fine spray. Germination usually takes 3 to 4 weeks, and do not allow the seedlings to dry out. Plant the seedlings into small pots only once they are quite big and strong enough. Transplant the young plants again into bigger pots when the roots have filled the small pots.
Streptocarpus can be propagated from a single leaf and the best results are from leaf cuttings taken in spring and early summer. Select healthy youngish leaves from the centre of the plant, and cut off using a sharp knife or blade. Remember that the most active region of the leaf is near the base where the growing region (meristem) is present, and so this area will yield the best rooting results. If it is a small leaf, insert the cut end of the leaf into a rooting hormone and then into the medium. Larger leaves can be cut into 3 cm strips. Always take note of which way the leaf cutting should be orientated, before dipping into a rooting hormone, and place firmly into the medium, but not too deep, as this will encourage rot. Alternatively, cut along either side of the midrib and treat in the same manner. A variety of mediums can be used as long as they are well drained. Sand, bark, palm fibre and polystyrene or vermiculite in different ratios are all suitable. At Kirstenbosch we use 40% bark, 40% fine leca and 20% river sand. Water the medium well and treat with a suitable fungicide before using. Depending on the species, plantlets will form along the base of the cut in 1 to 3 months.
When the plantlets are well established, the old leaf can be teased out from the medium and the plantlets potted up into a rich, well-drained soil mixture, usually between 6 to twelve months. Streptocarpus like a nutritious, well-aerated, medium with ample drainage of equal parts loam, sand, peat moss and well-rotted compost.
As they do not have deep roots, they often do better in shallow pots. Plants that have grown quite large can also be divided as a method of increasing them; do this in early spring and repot to grow on. Mature plants can lose their vigour after 3 to 5 years and propagation, as described above, can be used to replace them with younger plants.
Mealybug, aphids and caterpillars are the most troublesome pests of Streptocarpus, though none severely. Caterpillars can either be hand collected or sprayed with a suitable poison, aphids can be sprayed, or removed carefully, by running a thumb and forefinger along the flower stems—where they usually occur; if mealybug is found on any part of the plant, quickly remove the affected parts and treat with a suitable pesticide. Kirstenbosch has had great success in managing infestations by using biological control with the natural predators of mealybug.
Fungal infections are also a cause for concern; if fungus is found on any part of the plant, remove the affected parts and treat with a suitable fungicide.
Streptocarpus are usually only prone to pests and diseases when they are not being treated or grown correctly; any plant that is stressed, is more likely to come under attack. So avoid the following to reduce the occurrence of problems—overwatering, underfeeding, rootbound plants, lack of good air movement/circulation.
- Burtt, B.L. & Hilliard, O.M. 1971. Streptocarpus, an African plant study. University of Natal Press, Pietermaritzburg.
- Fabian, A. & Germishuizen, G. 1997. Wild flowers of northern South Africa. Fernwood Press, Vlaeberg.
- Leistner, O.A. (ed.). 2000. Seed plants of southern Africa: families and genera. Strelitzia 10. National Botanical Institute, Pretoria.
Plant Type: Perennial
SA Distribution: Limpopo, Mpumalanga
Soil type: Loam
Flowering season: Early Summer, Late Summer
Flower colour: White, Mauve/Lilac
Gardening skill: Average