Pleiospilos compactus
| Light | Very bright light; a few hours of direct sun suit it well |
|---|---|
| Water | Sparingly; drench only when the mix is bone dry, and keep dry in summer dormancy |
| Soil | Gritty, sharply draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9–11, protect from frost |
| Propagation | Seed (primary); division of older clumps |
| Toxicity | Generally regarded as non-toxic to cats and dogs |
Pleiospilos compactus is a small, clump-forming mimicry mesemb from the arid interior of South Africa, one of the so-called living rock or split rock plants prized by succulent collectors. Its thick, grey-green keeled leaves are more elongated than those of its relatives and are speckled with darker dots, so that a dormant plant looks convincingly like a weathered lump of stone until its bright yellow-orange flowers open. It belongs to the genus Pleiospilos in the ice-plant family Aizoaceae.
Description
Pleiospilos compactus forms compact clumps of one to a few leaf pairs. Each pair consists of two fleshy, boat-shaped leaves that are keeled beneath and flattened above, longer and more sharply angled than the near-hemispherical leaves of Pleiospilos nelii. The surface is a chalky grey to grey-green, dusted with numerous small dark dots (the "many-spotted" character that gives the genus its name), a camouflage that lets the plant blend into the surrounding gravel and shale.
Flowers appear from the centre of the leaf pair, typically in late summer to autumn. They are daisy-like, yellow to orange, and open in the afternoon, often carrying a faint coconut-like scent. As with other mesembs, the plant renews itself by producing a fresh leaf pair from within the old one, drawing on the old leaves until they shrivel to papery remains.
Distribution and habitat
The species is native to the semi-desert regions of South Africa, particularly the karroid scrub of the Eastern and Western Cape, where it grows on shaly, gravelly slopes and stony, mineral soils. These habitats are hot and dry for much of the year, with erratic rainfall, so the plants endure long droughts by contracting and relying on stored water in their swollen leaves. Their stone-like colouring provides camouflage against grazing animals and the fierce sun alike.
Cultivation
Pleiospilos compactus is a rewarding but water-sensitive plant, and overwatering is by far the commonest cause of loss. Grow it in a very free-draining, mostly mineral mix in a pot deep enough for its substantial taproot, and give it the brightest position you can, including some direct sun to keep the plant compact and well coloured.
Respect its seasonal rhythm: water sparingly in the cooler growing months of autumn and spring, and keep it dry through the heat of summer when it rests. A plant that puffs up, splits, or rots at the base is almost always being watered too often, especially while dormant. Allow the old leaf pair to be absorbed naturally rather than pulling it away. See Watering and Repotting for general technique.
Propagation
Seed is the usual and most reliable method. Fresh seed sown on a gritty, mineral surface and kept lightly moist and warm germinates readily, after which the tiny seedlings are grown on carefully with restrained watering. Older clumps that have offset into several heads can sometimes be divided, though the genus is not a prolific offsetter and most growers raise new plants from seed. See Propagation - seed and Propagation - offsets for fuller walkthroughs.
Common problems
- Rot — soft, translucent, collapsing leaves nearly always follow overwatering or watering during summer dormancy.
- Stacked or excess leaf pairs — too much water and too little light lead to multiple leaf pairs at once and a bloated, unnatural look; ease off water and increase light.
- Etiolation — insufficient light causes pale, elongated leaves that lose their stony compactness.
- Pests — mealybugs (white fluff between the leaves and at the roots) and occasionally root mealybugs are the main nuisances; see Pests and diseases.
See also
- Pleiospilos — the genus overview
- Pleiospilos nelii — the closely related, rounder-leaved split rock
- Soil and potting mix · Watering · Repotting · Propagation - seed · Propagation - offsets