Stenocereus eruca
| Light | Full sun; as bright as you can give it |
|---|---|
| Water | Sparingly; let the soil dry fully between waterings, keep dry in winter |
| Soil | Very free-draining, sandy mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; happiest in warm, frost-free conditions (roughly USDA zones 9b–11) |
| Propagation | Stem cuttings (easy); also seed |
| Toxicity | Not known to be toxic to cats or dogs |
Stenocereus eruca, the creeping devil, is one of the most extraordinary members of the genus Stenocereus — a cactus whose stems do not stand upright but lie flat and creep across the ground, rooting along the way and slowly advancing over the sand as the old end dies back. Endemic to the sandy plains of Baja California Sur in Mexico, it is often described as the closest thing the cactus family has to a plant that walks.
Description
Stenocereus eruca forms long, mostly prostrate stems that rest on the ground rather than growing erect. The stems are cylindrical and grey-green, and typically only the growing tip lifts a little way off the sand. Each stem is ribbed and armed with fierce, closely set spines — a flattened, dagger-like central spine backed by shorter radials — which give the creeping body a formidable, comb-like upper surface and inspire the common name.
The plant grows from the advancing tip while the older, trailing portion gradually withers and dies. New roots form along the underside of the stem as it moves forward, so a single individual can slowly migrate across the ground over many years, effectively cloning itself as older segments detach and root on their own. Large, funnel-shaped flowers open at night near the stem tips; they are pale — white, cream, or pale yellow, sometimes flushed pink — and are followed by spiny fruit.
Distribution and habitat
The species is endemic to Baja California Sur, Mexico, where it grows on the sandy flats and low dunes of the Magdalena Plain and nearby coastal lowlands. It favours open, sun-baked ground with loose, well-drained sandy soil, sprawling in colonies across terrain that offers little competition and plenty of light.
Its creeping, self-rooting habit is well suited to shifting sandy ground, allowing the plant to spread horizontally and colonise open flats where an upright columnar cactus would struggle. As with the whole cactus family, wild plants are protected under CITES; nursery-grown material is the right source for collectors.
Cultivation
The creeping devil is a striking specimen for growers who can give it what it wants: heat, strong light and very sharp drainage. Plant it in a wide, shallow container or bed using a gritty, sandy, mostly mineral mix, and grow it in the brightest position available so the stems stay compact and well-armed. Because the plant naturally sprawls, a broad, low pot showcases its habit better than a deep one.
Water thoroughly during warm active growth once the soil has dried, then allow it to dry out again; keep it dry and warm through the winter rest to avoid rot. Handle with real care — the flattened central spines are sharp and the low-slung stems put them right where hands tend to go. See Watering and Repotting for general technique.
Propagation
Vegetative propagation is easy and mirrors the way the plant behaves in the wild. A detached length of stem, allowed to callus at the cut end, will root readily when laid on or partly set into a gritty mix — see Propagation — cuttings. Seed is also viable where fresh, ripe seed can be had; sow on a warm mineral surface as for other columnar cacti (see Propagation — seed).
Common problems
- Rot — the usual killer, brought on by wet, poorly drained soil or watering during cold, dark spells. Keep drainage sharp and the winter rest dry.
- Etiolation — too little light makes the stems thin, pale and weakly spined, spoiling the plant's characteristic armoured look.
- Pests — mealybugs (white fluff around the spines and growing tip) and scale are the most likely visitors; watch for spider mites in hot, dry, still air. See Pests and diseases.
See also
- Stenocereus — the genus overview
- Propagation — cuttings · Soil and potting mix · Watering · Repotting