Melocactus intortus
| Light | Very bright light to full sun |
|---|---|
| Water | Moderate in warm growth; keep drier and warmer in winter |
| Soil | Fast-draining mineral mix, slightly alkaline tolerant (see Soil and potting mix) |
| Temperature | Warmth-loving; keep well above freezing, USDA zones 10–11 |
| Propagation | Seed |
| Toxicity | Non-toxic to cats and dogs |
Melocactus intortus is a large Caribbean melon cactus, instantly recognised in maturity by the tall, wool-and-bristle cap — the cephalium — that crowns its ribbed green body. This cap gives the plant its enduring common name, the Turk's cap cactus, and it is one of the signature succulents of West Indian coasts and rocky headlands.
Description
Melocactus intortus forms a solitary, more or less spherical to barrel-shaped body that becomes cylindrical with age, reaching a substantial size — among the largest in its genus. The body is a firm, glossy green divided into a good number of broad, prominent ribs, each armed with stout, radiating spines that curve and can be quite fierce on well-grown plants.
The most distinctive feature appears only at maturity. Once the plant reaches flowering age it stops enlarging its green body and instead produces a cephalium at the apex: a dense terminal cap of white wool shot through with fine reddish bristles. The cephalium grows taller year on year while the body beneath stays much the same size, producing the top-heavy "Turk's cap" silhouette. Small pink flowers emerge from the wool, followed by slender pink to reddish berry-like fruits that push up out of the cap.
Distribution and habitat
The species is native to the Caribbean, ranging from the Bahamas and Puerto Rico through the Lesser Antilles. It is a plant of hot, exposed, low-elevation sites — coastal cliffs, rocky slopes and thin soils over limestone — where it endures strong sun, salt-laden wind and long dry spells. These origins explain its love of heat, sharp drainage and bright light in cultivation, and its dislike of cold, damp conditions.
Like all cacti it is listed under CITES Appendix II, and wild populations are best left undisturbed; nursery-raised, seed-grown plants are the proper source for collectors.
Cultivation
Grow Melocactus intortus as a warmth-loving, sun-loving plant. It wants the brightest position you can give it and a very free-draining, largely mineral mix; a little added limestone or grit suits its limestone-country habits. Water moderately through the warm growing season, always letting the soil dry between waterings, then keep the plant considerably drier through winter.
The key point with melon cacti is temperature: they resent cold, and cold combined with moisture leads quickly to rot. Keep this species reliably warm and never let it sit wet and chilly. In cooler climates it is best grown under glass or brought indoors for the winter. See Watering and Repotting for general technique.
A note on the cephalium: it is a permanent feature and a sign the plant has matured. A capped plant will not grow taller in the body, so buy for the size body you want. Handle capped plants gently, as the wool and bristles of the cephalium are easily soiled or crushed.
Propagation
Seed is the standard and essentially the only practical method. Melocactus species are solitary and do not offset, so there is no vegetative route in normal cultivation. Sow on a warm, mineral surface kept humid and bright; the seedlings appreciate steady warmth. Growing melon cacti from seed to a caphead takes patience, but it is the reliable way to raise them. See Propagation — seed for a full walkthrough.
Common problems
- Rot — the chief killer, almost always from cold combined with excess moisture or a slow-draining mix; the body softens and discolours.
- Cold damage — corky scarring or collapse after exposure to low temperatures; this is a strictly tender plant.
- Pests — mealybugs (white fluff among the spines and at the base) and red spider mites (fine webbing, bronzed skin) are the usual offenders. See Pests and diseases.
See also
- Melocactus — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Pests and diseases