Euphorbia clandestina
| Light | Bright light to a few hours of direct sun; can take full sun once acclimatised |
|---|---|
| Water | Moderately in growth, letting the mix dry between waterings; keep drier when resting |
| Soil | Fast-draining, gritty mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9b–11 |
| Propagation | Seed; occasionally cuttings |
| Toxicity | Toxic — milky latex irritates skin and eyes and is harmful if swallowed |
Euphorbia clandestina is an upright, usually single-stemmed succulent from the winter-rainfall regions of the Western Cape, South Africa, grown for its distinctive knobbly column and neat crown of foliage. The tapering green stem is closely packed with raised tubercles arranged in spiralling rows, each tubercle tipped with a leaf, and is topped by a crown of narrow, keeled leaves, giving mature plants a curious, almost palm-like silhouette. As the plant grows, the lower leaves are shed to reveal the patterned, tubercled trunk.
Description
Euphorbia clandestina typically grows as a solitary, erect stem that thickens with age and can reach up to about 800 mm (0.8 m) tall in old specimens, with a stem up to around 50 mm in diameter, though most cultivated plants are far smaller. The whole surface is covered in prominent tubercles arranged in several spiralling rows, each tubercle tipped with a leaf; as the plant grows, the lower leaves are shed and a crown is retained near the apex, so the bare, patterned trunk is revealed over time.
The leaves are narrow, linear-lanceolate and keeled, borne in a crown at the stem tip; the plant is more or less evergreen, though the lower leaves drop over time to expose the tubercled stem. Like other members of the genus, the plant carries a milky white latex throughout its tissues. The flowers are the small, pale greenish-yellow cyathia typical of Euphorbia, borne stalkless (sessile) among the tubercles near the growing point rather than being showy.
Distribution and habitat
The species is native to the Western Cape of South Africa, where it grows on rocky hills and stony lower slopes among low shrubs and karroid scrub. It occupies a winter-rainfall region, so in habitat it endures long, hot, dry summers and receives most of its moisture in the cooler winter months, a rhythm that shapes how it is best watered in cultivation.
Cultivation
Euphorbia clandestina is an undemanding and rewarding plant for anyone with a bright, sunny spot. Grow it in a very free-draining, mostly mineral mix in a pot that drains freely, and give it bright light with several hours of direct sun for the tightest, most characterful growth — too little light produces a soft, stretched stem with widely spaced tubercles.
Water moderately while the plant is in active growth and showing leaves, always letting the mix dry out between waterings, and reduce water during its dry rest, when growth slows and some of the lower leaves may drop. Keep it dry and frost-free through the coldest part of the year. As a winter grower in origin it may be most active in the cooler months, but in cultivation many plants adapt to the light and warmth they are given; watch the plant rather than the calendar and water when it is clearly growing. See Watering and Repotting for general technique.
Take care when handling or pruning: the milky latex is an irritant to skin and especially the eyes, so wash off any sap promptly and keep it away from your face and from pets. See Pests and diseases for common issues.
Propagation
Seed is the most reliable method and produces naturally single-stemmed plants; sow onto a warm, gritty surface kept lightly moist. Cuttings are possible but less commonly used, as the species does not readily branch — allow any cutting's cut end to callus for a week or more before setting it in a dry mineral mix. Blot the bleeding latex first, since the flow of sap can hinder rooting. See Propagation — seed and Propagation — cuttings for full walkthroughs.
Common problems
- Rot — the commonest cause of loss, almost always from overwatering, a slow-draining mix, or water given during the dry rest; the stem softens and discolours from the base.
- Etiolation — too little light makes the stem thin and elongated with widely spaced tubercles, losing its compact, knobbly character.
- Pests — mealybugs (white fluff among the leaves and in leaf scars) and spider mites are the usual culprits; root mealybugs can also trouble the roots.
See also
- Euphorbia — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — cuttings · Pests and diseases