Huernia pillansii
| Light | Bright, filtered light; some direct sun with acclimatisation |
|---|---|
| Water | Sparingly in growth; keep dry and rested in winter |
| Soil | Very free-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above about 7 °C; USDA zones 10–11 |
| Propagation | Stem cuttings (primary); seed |
| Toxicity | Generally regarded as non-toxic; sap may irritate |
Huernia pillansii, sometimes called the cocklebur, is a low, clump-forming succulent from the Karoo of South Africa, grown for its unusual soft-bristled stems and its curious papillose star flowers. Its short cylindrical stems are densely covered in soft, spine-tipped tubercles that give the plant a shaggy, bur-like look, and in season it produces small five-lobed blooms, cream to yellow flushed red and studded all over with tiny fleshy papillae. It belongs to the genus Huernia, one of the stapeliads within the family Apocynaceae.
Description
Huernia pillansii forms tight cushions of erect to slightly leaning stems, each only a few centimetres tall and roughly finger-thick. Unlike the more angular, toothed stems of many stapeliads, the stems here are near-cylindrical and completely obscured by numerous soft tubercles, each drawn out into a slender, bristle-like, non-woody spine. The overall texture is soft to the touch and distinctly hairy in appearance — the feature that sets the species apart at a glance.
The flowers arise low on the stems and are shallowly bell- to star-shaped, typically 2–3 cm across, with five broad triangular lobes. Colour ranges from pale cream and yellow to deeper reddish tones, and the entire inner face is covered in small rounded papillae, giving the corolla a warty, tactile surface. Like other stapeliads the flowers are fly-pollinated and can carry a faint carrion scent, though it is mild in this species compared with some relatives.
Distribution and habitat
The species is native to the arid interior of South Africa, in the Karoo of the Western and Eastern Cape. There it grows in dry, stony ground, often tucked among rocks or beneath the light shade of low nurse shrubs that shelter it from the harshest sun. The climate is one of hot, dry summers, cool winters and low, erratic rainfall, and the plants endure long dry spells by drawing on the moisture stored in their fleshy stems.
Cultivation
Huernia pillansii is an undemanding plant by stapeliad standards, provided its roots are never left wet. Grow it in a very free-draining, mostly mineral mix in a shallow pot, since the shallow root system prefers to spread rather than go deep. Give it bright light — more than most stapeliads enjoy — with a little protection from the fiercest midday sun, which helps keep the compact, well-coloured habit; too much shade produces weak, etiolated stems.
Water moderately through the warm growing season, always letting the mix dry out between waterings, and keep the plant nearly dry and rested through winter. Cold, damp conditions are the chief danger: keep it above roughly 7 °C and dry when temperatures fall. See Watering and Repotting for general technique. Rot at the base is the usual cause of loss, so err on the side of underwatering.
Propagation
The easiest method is by stem cuttings. Detach a healthy stem or small cluster, let the cut surface dry and callus for a few days, then set it in a dry, gritty mix and water only lightly until roots form. Established clumps can also be divided when repotting. Seed is possible where flowers are pollinated and pods set, but cuttings are faster and keep the plant true. See Propagation — cuttings and Propagation — offsets for details.
Common problems
- Rot — almost always from overwatering, a slow-draining mix, or cold wet conditions; stems soften, blacken and collapse at the base.
- Etiolation — too little light makes the stems stretch and lose their tight, bristly form.
- Pests — mealybugs (white fluff between the tubercles and at the roots) are the most common problem; watch also for root mealybugs on the roots.
See also
- Huernia — the genus overview
- Propagation — cuttings · Propagation — offsets · Soil and potting mix · Watering · Repotting · Pests and diseases