Turbinicarpus alonsoi
| Light | Bright light with some shade from the fiercest afternoon sun |
|---|---|
| Water | Sparingly; allow to dry fully between waterings, dry rest in winter |
| Soil | Very free-draining, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; a cool, dry winter is best |
| Propagation | Seed (primary); grafting to speed slow seedlings |
| Toxicity | Non-toxic to cats and dogs |
Turbinicarpus alonsoi is a small, geophytic cactus from a tiny area in the Mexican state of Guanajuato, described only in 1996 and prized by collectors for its unusual body. Its most distinctive feature is the arrangement of broad, flattened, triangular tubercles that spiral outward from a woolly crown, from which large, showy magenta flowers open in season. Like its relatives it belongs to the genus Turbinicarpus, a group of miniature Mexican cacti much loved in cultivation.
Description
Turbinicarpus alonsoi forms a small, mostly solitary plant that sits low against the ground, retracting into the soil during drought so that little more than the flat top shows. The body is topped by broad, angular tubercles that are noticeably flattened and triangular, arranged in a neat spiral and separated by soft wool in the crown. A few flattened, papery spines — soft and blunt rather than sharp — sit at the tips of the tubercles rather than clothing the whole plant.
The flowers are large in proportion to the body, a vivid magenta to purplish-pink, and open around the woolly apex in the warmer months. As with many geophytic cacti, a substantial part of the plant is a thickened, tuberous rootstock hidden below the surface.
Distribution and habitat
The species is endemic to a very small area in Guanajuato, central Mexico, where it grows in rocky, well-drained ground among sparse vegetation. Its extremely limited range makes wild populations vulnerable to collection and habitat disturbance.
The entire genus Turbinicarpus is listed on CITES Appendix I — a stricter listing than the Appendix II that covers the cactus family as a whole — meaning international trade in wild-collected plants is tightly restricted. Nursery-propagated plants, however, are widely available, inexpensive and entirely legal to own and trade; plants should never be taken from the wild.
Cultivation
Turbinicarpus alonsoi is a rewarding miniature but, like most of its genus, unforgiving of overwatering — the tuberous root rots easily if kept damp. Grow it in a very free-draining, mostly mineral mix in a pot deep enough to accommodate the taproot, in bright light with a little shade from the most intense summer sun. Water thoroughly only once the soil has dried out completely, then allow it to dry again; keep the plant dry and cool through winter to encourage flowering and prevent rot. See Watering and Repotting for general technique.
Because seedlings are slow, some growers graft young plants onto a vigorous rootstock to build them up quickly, then grow them on their own roots later.
Propagation
Seed is the standard method. The fine seeds germinate readily on a warm, mineral surface kept humid, and seed-raising is how the species is normally increased in collections. As a largely solitary plant it rarely offsets, so vegetative propagation is uncommon outside of grafting. See Propagation — seed for a full walkthrough, and Propagation — offsets for the occasional clustering plant.
Common problems
- Rot — almost always from overwatering or a slow-draining mix; the plant or its tuberous root softens and browns, often from the base.
- Etiolation — too little light makes the body pale and pushes it upward, distorting the neat spiral of tubercles.
- Pests — red spider mites (fine webbing, bronzed skin) and mealybugs (white fluff in the crown and among the roots) are the usual culprits.
See also
- Turbinicarpus — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting