Euphorbia stellata
| Light | Bright light to some direct sun; more light keeps the branches compact and well-coloured |
|---|---|
| Water | Moderate in growth, sparingly once the branches harden; keep dry through winter dormancy |
| Soil | Very free-draining, gritty mineral mix |
| Temperature | Keep above freezing; USDA zones 9b–11 |
| Propagation | Seed; cuttings |
| Toxicity | Toxic; the milky latex irritates skin, eyes and mucous membranes (see Pests and diseases and handling notes) |
Euphorbia stellata is a small, clump-forming caudiciform succulent from South Africa, prized by collectors for the way its swollen underground tuber sends up clusters of flattened, spreading branches. Each branch is narrow, ribbon-like and edged with small teeth, and the branches radiate outward in a low star-shaped arrangement — the trait that gives the species its name. When the tuber is lifted and displayed above the soil, as growers often do, the plant takes on a striking sculptural look.
Description
Euphorbia stellata grows from a large, fleshy tuberous rootstock (a caudex) that in habitat sits mostly buried, with only the branch cluster showing at the surface. From the crown of this tuber emerge numerous flattened, strap-like branches, typically only about a centimetre wide, two-ribbed down the middle and lined along the margins with short, firm teeth armed with small paired spines. The branch surface is dark green, often marked with a pale, feathery whitish pattern.
The branches spread and sprawl outward rather than growing upright, forming a low, radiating clump. Like most in the genus, the plant contains a milky white latex that flows freely from any cut or break. The flowers are the tiny specialised structures typical of Euphorbia, called cyathia — small and yellow-green, and modest compared with the architecture of the plant itself.
Distribution and habitat
Euphorbia stellata is native to the Eastern Cape of South Africa, where it grows in dry scrub and grassland, rooting in well-drained, often stony ground. In the wild the tuber is drawn down into the soil, protecting it from heat and drought while the slim branches emerge only seasonally. This habit — a fat water-storing base hidden below and expendable top growth above — is a classic adaptation to a climate of hard dry seasons broken by brief rains.
Cultivation
Euphorbia stellata is an accommodating grower by caudiciform standards, but it rewards restraint with water. Plant it in a very open, gritty mix in a pot deep enough for the tuber, and give it bright light with some direct sun; strong light keeps the branches short and richly coloured, while too little makes them stretch and go floppy. Water moderately while the plant is actively growing, letting the mix dry between waterings, and taper off as the branches harden. Through the cool, dark months keep it dry and let it rest — wet, cold roots are the quickest way to lose the tuber to rot.
Many growers gradually lift the caudex above the soil line over successive repottings to show it off, though the tuber colours and toughens once exposed and should be raised slowly. Always handle the plant with care: the latex is a genuine irritant, so wear gloves and keep it away from eyes and mouth. See Watering and Repotting for general technique.
Propagation
The species can be grown from seed, which is the best route to a naturally fat, symmetrical tuber, though seed is uncommon in cultivation because germination needs high, steady warmth. Branch cuttings root fairly readily: let the cut end dry and callus for several days first to seal the weeping latex, then set it in a barely-moist gritty mix. Cuttings tend to grow a thinner, more fibrous rootstock than seedlings.
Common problems
- Rot — the usual killer, almost always from overwatering or a cold, wet, poorly-draining mix; the tuber softens and collapses.
- Etiolation — in too little light the branches stretch, thin out and sprawl weakly, losing the tight star form.
- Pests — mealybugs (white fluff among the branches and at the crown) and spider mites are the common offenders; see Pests and diseases.
- Latex irritation — not a plant problem but a grower one: the sap stings skin and eyes, so handle cut plants carefully.
See also
- Euphorbia — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — cuttings · Pests and diseases