Neobuxbaumia euphorbioides
| Light | Bright light to full sun once established |
|---|---|
| Water | Moderate in the warm season; allow to dry between waterings, keep dry in winter |
| Soil | Fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; hardy to about −2 °C (USDA zones 10–11) |
| Propagation | Seed (primary); cuttings possible but slow to root |
| Toxicity | Non-toxic to cats and dogs |
Neobuxbaumia euphorbioides is a slender, ribbed, mostly solitary columnar cactus from eastern Mexico, grown for the neat, almost architectural symmetry of its ribbed column. It has at times been separated into its own monotypic genus as Rooksbya euphorbioides, and the name refers to its resemblance to a spurge (Euphorbia) rather than to any close relationship. It belongs to the small Mexican genus Neobuxbaumia.
Description
Neobuxbaumia euphorbioides typically grows as an unbranched, upright column, usually staying single for many years and only occasionally branching from the base or after damage. The stem is green, often with a greyish, glaucous cast, and carries a modest number of prominent ribs — usually about eight to ten — with slightly wavy, crenate crests, giving the plant its tidy, evenly fluted profile. Woolly areoles run in neat vertical lines along the rib crests, bearing short, stiff spines that are more decorative than fierce.
Mature plants can reach several metres tall in habitat, old specimens occasionally approaching seven metres, though potted specimens grow slowly and stay much smaller for a long time. Funnel- to bell-shaped flowers open near the top of the stem, generally in shades of pink to reddish, followed by fleshy fruit. The overall effect — a ribbed column standing like a classical pillar — is what makes the species a favourite with growers who like formal, sculptural cacti.
Distribution and habitat
The species is native to eastern Mexico, chiefly the states of Veracruz and Tamaulipas, where it grows in seasonally dry (low) tropical forest, often on rocky, sometimes basaltic slopes at around 300–600 metres. In these habitats it endures strong sun, seasonal drought and warm temperatures, rooting in gritty, sharply drained ground. Like most columnar cacti of the region, it experiences a distinct dry season during which it takes up little water.
Cultivation
Neobuxbaumia euphorbioides is a straightforward, rewarding grower given warmth, light and restraint with the watering can. Plant it in a very free-draining, mostly mineral mix and give it the brightest position you can; young plants appreciate a little protection from the most intense afternoon sun, but the species colours and grows best in strong light. Water thoroughly during the warm months once the soil has dried out, then allow it to dry again before repeating.
Through winter keep the plant dry and on the cool side to prevent rot and encourage sturdy, well-ribbed growth. As with most columnar cacti, the commonest mistake is keeping the roots wet and cold at the same time. See Watering and Repotting for general technique.
Propagation
Seed is the usual and most reliable method: sown on a warm, mineral surface kept humid, the seedlings come up readily and grow into characteristically ribbed little columns. Cuttings can be taken from branched or damaged plants — allow the cut surface to callus well before setting it on barely moist mix — but rooting is slow and the species branches only rarely, so most plants in cultivation are seed-raised. See Propagation — seed and Propagation — cuttings for full walkthroughs.
Common problems
- Rot — the main killer, almost always from overwatering, a slow-draining mix or cold wet roots in winter; the base softens and discolours.
- Etiolation — too little light makes new growth pale, thin and drawn out, spoiling the plant's even, ribbed symmetry.
- Pests — mealybugs (white fluff in the areoles) and red spider mites (fine webbing, bronzed skin) are the usual offenders on columnar cacti.
See also
- Neobuxbaumia — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — cuttings