Piaranthus punctatus
| Light | Bright light with shade from harsh midday sun; too much direct sun scorches the soft stems |
|---|---|
| Water | Sparingly in the growing season; keep dry through the coldest months |
| Soil | Very free-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above about 10 °C; frost-tender, USDA zones 10–11 |
| Propagation | Stem cuttings and division of clumps; also seed |
| Toxicity | No serious toxicity reported; sap may mildly irritate |
Piaranthus punctatus is a small, low-growing stapeliad — a member of the milkweed family Apocynaceae — that forms spreading mats of short, chunky, angled stems and produces pale, purple-spotted, star-shaped flowers close to the ground. Like other members of the genus Piaranthus, it belongs to the succulent tribe Ceropegieae.
Description
Piaranthus punctatus grows as a clump of short, fleshy stems, each only a few centimetres long, thick and bluntly four-angled with soft rounded teeth along the edges. The stems are typically grey-green, often tinged purplish or bronze in strong light, and they branch and sprawl to form loose, spreading cushions rather than upright plants.
The flowers are the main attraction. They open flat and star-like, with five triangular lobes, and are cream to pale yellowish in ground colour, marked with reddish-purple to maroon spots and short transverse bars — the "punctate" pattern that gives the species its name. As with many stapeliads the blooms carry a faint scent that attracts flies as pollinators, though it is far milder than the notorious carrion-flowers of some related genera.
Distribution and habitat
The genus Piaranthus is native to the drier parts of southern Africa, and P. punctatus occurs in arid, sandy and rocky habitats within this range. Plants typically grow tucked among rocks or in the shelter of low shrubs, where the surrounding vegetation gives them some protection from the most intense sun and the mats can creep across gritty, well-drained ground.
Cultivation
Piaranthus punctatus is grown much like other small stapeliads and is not difficult once its dislike of excess moisture is respected. Give it a very free-draining, mostly mineral mix in a shallow pot, and site it in bright light with shade from the fiercest midday sun — the soft stems scorch easily but etiolate and lose their colour in too little light.
Water regularly but lightly through the warm growing season, always letting the mix dry out between waterings, and keep the plant dry and cool during winter dormancy. Overwatering, cold-wet conditions and poorly draining soil are the usual causes of loss. See Watering and Repotting for general technique.
Propagation
Propagation is easy from stem cuttings: detach a healthy segment, let the cut end callus for a few days, then set it on a gritty, barely-moist mix to root. Established clumps can also be lifted and divided. Seed is another option where fresh seed is available, sown on a warm, mineral surface. See Propagation — cuttings and Propagation — offsets for full walkthroughs.
Common problems
- Rot — the most common killer, almost always from overwatering, a slow-draining mix, or cold-wet winter conditions; affected stems turn soft, translucent and brown.
- Etiolation — too little light causes thin, stretched, pale stems and poor flowering.
- Pests — mealybugs (white fluff between the stems and at the roots) and root mealybugs are the usual troublemakers; watch also for aphids on the flower buds. See Pests and diseases.
See also
- Piaranthus — the genus overview
- Stapeliads — the wider group of stem-succulent Apocynaceae
- Soil and potting mix · Watering · Propagation — cuttings · Propagation — offsets · Repotting · Pests and diseases