Duvalia caespitosa
| Light | Bright light with some shade from the harshest afternoon sun |
|---|---|
| Water | Sparingly; let the mix dry fully between waterings, keep dry in winter |
| Soil | Very free-draining, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep frost-free and warm; roughly USDA zones 10–11 |
| Propagation | Cuttings and division of the clump; also seed |
| Toxicity | Not known to be toxic to cats or dogs |
Duvalia caespitosa is a small, clump-forming stapeliad in the milkweed family (Duvalia, Apocynaceae), grown for its low mats of angular grey-green stems and its curious, dark reddish, star-shaped flowers. It spreads into dense, low cushions rather than climbing or growing tall, making it a compact and easygoing member of the carrion-flower group.
Description
Duvalia caespitosa forms low, tufted mats of short stems that branch and root freely at the base, gradually building up into a spreading clump — the caespitosa epithet simply means "growing in tufts". Each stem is small, soft-fleshed and bluntly four- to five-angled, usually green to grey-green and often flushed with reddish or purplish tones in strong light. The angles carry small, soft tooth-like tubercles rather than true spines.
The flowers are the main attraction. They appear low down near the stems, singly or in pairs, and are modest in size. The five corolla lobes are narrow and typically fold back or inward, so the bloom reads as a star of thin, spike-like rays rather than a broad flat disc. They are dark red to reddish-brown, sometimes almost blackish, and surround a fleshy raised annulus and central crown (corona) that is characteristic of the genus. Like most stapeliads, the blooms are pollinated by flies and can carry a faint unpleasant scent, though it is far milder than in the big Stapelia species.
Distribution and habitat
The species is native to South Africa — mainly the Western and Eastern Cape, extending into the Free State — and to southern Lesotho, where it grows in dry, open Karoo country — typically tucked among rocks, gravel and low scrub that give it a little shade and protection. In habitat it experiences hot, dry conditions with seasonal rainfall, and the mat-forming habit lets it hug the ground and creep into sheltered pockets of gritty soil. Several regional forms, subspecies and varieties have been recognised within its range, and it is closely allied to other small clumping Duvalia species.
Cultivation
Duvalia caespitosa is an undemanding little plant if kept on the dry side. Grow it in a shallow pot in a very free-draining, largely mineral mix, in bright light with some shading from scorching midday sun — a touch of shade also brings out the best stem colour without etiolation. Water thoroughly only once the mix has dried right out during the warm growing season, then reduce watering sharply and keep the plant nearly dry through the cool winter months, when it is most vulnerable to rot.
Warmth and airflow matter: like all stapeliads it dislikes cold, damp, stagnant conditions, which invite stem rot. Keep it frost-free and give it a snug pot so the mix dries quickly. See Watering and Repotting for general technique.
Propagation
The easiest method is vegetative. Because the clump roots as it spreads, rooted pieces can simply be lifted and divided, and unrooted stem cuttings root readily once the cut surface has been left to callus for a few days on dry, gritty mix. It can also be raised from seed when the distinctive paired stapeliad horn-like pods ripen and release their tufted seeds, though cuttings and division are quicker and keep a chosen form true.
Common problems
- Rot — by far the commonest killer, caused by overwatering, a slow-draining mix or cold damp conditions; stems go soft, translucent and collapse.
- Mealybugs — white cottony pests hide among the crowded stems and in the root zone; check regularly (see Pests and diseases).
- Shrivelling — thin, wrinkled stems usually mean the plant has been kept too dry for too long, or has lost roots to earlier rot.
See also
- Duvalia — the genus overview
- Stapelia · Ceropegia — related stapeliads
- Soil and potting mix · Watering · Propagation — cuttings · Propagation — seed · Pests and diseases