Duvalia corderoyi
| Light | Bright light with some shade from harsh midday sun; can scorch in full desert sun |
|---|---|
| Water | Moderate in the growing season, letting the mix dry between waterings; keep nearly dry in winter |
| Soil | Very free-draining, gritty mineral mix (see Soil and potting mix) |
| Temperature | Keep above roughly 8 °C; frost-tender, USDA zones 10–11 |
| Propagation | Stem cuttings, division of clumps, and seed |
| Toxicity | Not known to be toxic to cats and dogs; the sap is watery rather than a milky latex |
Duvalia corderoyi is a compact clump-forming stapeliad in the milkweed family Apocynaceae, endemic to South Africa. It forms low mats of short, plump grey-green stems and produces relatively large, striking star-shaped flowers of brick-red to red-brown — the largest of any southern African species of the genus — with the centre densely bearded with pale, soft hairs around a raised ring (the annulus). Like its relatives in the genus Duvalia, it is a member of the group of stem-succulent asclepiads prized by collectors for their intricate, often carrion-scented blooms.
Description
Duvalia corderoyi is a small, spreading succulent that builds up clusters of stubby stems rather than tall columns. Each stem is short and rounded to somewhat angular, greyish- to bluish-green, and edged with low, blunt teeth typical of the genus. The stems root as they sprawl, so an established plant slowly forms a dense low cushion or mat.
The flowers are the main attraction. They are among the largest in the genus — generally at least 3 cm across — and boldly coloured brick-red to maroon, with narrow, spreading, star-like lobes that are often finely wrinkled or textured. At the centre sits the annulus, a raised, doughnut-like ring, and the whole centre is thickly covered with a dense beard of long, soft pale (white to purplish) hairs — the feature that gives the plant its common name of hairy-flowered stapeliad. As with many stapeliads, the flowers give off a faint scent to attract the flies that pollinate them.
Distribution and habitat
The species is endemic to South Africa, where it is widespread across the Great Karoo and the adjacent interior — from the Eastern and Northern Cape through the Western Cape to the Free State — growing in dry, warm habitats. Plants typically shelter among rocks, in the light shade of low shrubs, or nestled into gritty, well-drained ground (often among dolerite stones) where their spreading stems can creep between stones. These are arid- to semi-arid conditions with a distinct dry season, and the plants are adapted to store water in their fleshy stems and wait out drought. The species is common and widespread, and is not considered threatened.
Cultivation
Duvalia corderoyi is grown much like other Duvalia and stapeliad succulents. The single most important thing is drainage: use a very open, mostly mineral mix in a shallow or wide pot that suits its spreading habit. Give it bright light with a little shade from the fiercest midday sun — too much shade produces weak, etiolated growth and few flowers, while unrelenting full sun can scorch the stems.
Water moderately during the warm growing season, always allowing the mix to dry before watering again, and keep the plant nearly dry through the cool months. Cold, damp conditions are the main enemy, so keep it above about 8 °C and protect it from frost. See Watering and Repotting for general technique.
Propagation
Propagation is easy and one of the pleasures of growing stapeliads. Detach a stem or a small clump of stems, let the cut end callus for a day or two, then set it on or just into a gritty mix to root — see Propagation — cuttings. Established clumps can also simply be divided at repotting time. Fresh seed germinates readily when sown on a warm, well-drained surface, though seed-grown plants take longer to reach flowering size (Propagation — seed).
Common problems
- Stem rot — by far the commonest killer, caused by overwatering, a poorly draining mix, or cold wet conditions; affected stems go soft, translucent and brown. Remove rot promptly and re-root healthy stems.
- Etiolation — too little light makes stems thin, pale and stretched, and discourages flowering.
- Pests — mealybugs (including root mealybugs) are the usual trouble, hiding between crowded stems and in the roots; watch also for spider mites in hot, dry air. See Pests and diseases.
See also
- Duvalia — the genus overview
- Stapeliad — the wider group of stem-succulent asclepiads
- Soil and potting mix · Watering · Propagation — cuttings · Propagation — offsets · Repotting · Pests and diseases