Lapidaria margaretae
| Light | Very bright light; full sun to light shade, especially during the autumn and spring growth |
|---|---|
| Water | Sparingly; keep dry through the hot summer rest, water in autumn and spring (see Watering) |
| Soil | Very gritty, fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; frost-tender, USDA zones 9b–11 |
| Propagation | Seed (primary); see Propagation — seed |
| Toxicity | Not known to be toxic to cats or dogs |
Lapidaria margaretae, commonly known as the Karoo rose, is a small, clump-forming succulent from the arid borderlands of South Africa and Namibia, and the only species in its genus. It stacks a few pairs of thick, angular, blue-grey to pinkish leaves into a stone-like body, from which emerge large, glossy golden-yellow flowers that can be wider than the plant itself. It belongs to the mesemb group of the ice-plant family (Aizoaceae) and is a close relative of the true living stones.
Description
Lapidaria margaretae is a compact, slow-growing succulent that forms small clumps of a few heads. Each head is built from one to four pairs of exceptionally thick, keeled leaves arranged in a cross, giving the plant a chunky, faceted, almost carved appearance. The leaf surfaces are smooth and semi-translucent, coloured a soft blue-grey that often flushes pink, mauve or cream in strong light, so that a resting plant blends convincingly with the surrounding pebbles — a form of camouflage shared with its living-stone relatives.
In autumn the plant produces its striking flowers: daisy-like, glossy golden-yellow, sometimes with a paler centre, and remarkably large for the size of the body, frequently exceeding it in diameter. The flowers open in the afternoon and last several days. Like other mesembs, the plant renews its leaves in a cycle, drawing on the old pair as the new growth forms.
Distribution and habitat
The species grows in an arid, transitional-rainfall borderland where South Africa meets southern Namibia — the area around Warmbad and the adjacent Northern Cape — on white quartz flats and in the fissures of rocky ground, under intense sun and very low rainfall (around 250 mm a year). It roots among stones in sparse, well-drained ground, relying on stored water in its swollen leaves to carry it through long dry spells, growing in the milder spring and autumn and resting through both the hot summer and the cold winter. In habitat the plants are easily overlooked, sitting flush with the surface among the pebbles until they flower.
Cultivation
Lapidaria margaretae is grown much like Lithops and other stone-mimic mesembs, and rewards a grower who resists the urge to water. Plant it in a very gritty, mostly mineral mix in a pot deep enough for its taproot-like base, and give it the brightest position available — full sun is generally welcome and keeps the body compact and colourful. Too little light causes soft, elongated, dull-coloured growth.
Watering follows the plant's natural rhythm: water in autumn as it comes into growth and flower, ease off, then keep it essentially dry through the heat of summer when it rests — and keep it largely dry again through the cold of winter, its other dormant period. Never let water sit around the body, and avoid watering while a new pair of leaves is drawing on the old one. Good airflow and a dry winter atmosphere help prevent rot, which is by far the most common cause of loss. See Watering and Repotting for general technique.
Propagation
Seed is the usual and most reliable method. The fine seed is sown on a gritty, mineral surface kept lightly moist and warm until germination, after which seedlings are grown on carefully with sparing water. Because the plant is naturally slow and clumps only modestly, division of established clumps is possible but uncommon. See Propagation — seed for a full walkthrough.
Common problems
- Rot — almost always from overwatering, watering during the summer rest, or a slow-draining mix; the body goes soft and translucent from the base.
- Etiolation — insufficient light makes the leaves swell, elongate and lose their compact, stony form and colour.
- Split or scarred leaves — sudden heavy watering after a dry spell can cause the leaves to swell and split.
- Pests — mealybugs (white fluff between and beneath the leaf pairs) and root mealybugs are the usual culprits; see Pests and diseases.
See also
- Lapidaria — the genus overview
- Lithops — the living stones, close mesemb relatives
- Soil and potting mix · Watering · Propagation — seed · Repotting · Pests and diseases