Sulcorebutia tiraquensis
| Light | Bright light with a few hours of full sun; some protection from harsh midday summer sun |
|---|---|
| Water | Regularly in the growing season once the mix has dried; keep bone-dry and cool in winter |
| Soil | Gritty, fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; tolerates cool, dry winters — roughly USDA zones 9a–11 |
| Propagation | Seed and offsets; also grown from grafts |
| Toxicity | Non-toxic to cats and dogs |
Sulcorebutia tiraquensis is a small, clustering cactus from the Bolivian Andes, and one of the showier members of its genus. It is prized for its long, dense, often comb-like spines and its vivid magenta to purple-red flowers, which open in profusion in spring. It belongs to the high-altitude genus Sulcorebutia, a group of dwarf South American cacti beloved by collectors for their compact bodies and brilliant blooms.
Description
Sulcorebutia tiraquensis forms a small, globular to shortly cylindrical body, usually a few centimetres across, that offsets with age to build up tight clumps. The body is divided into low, spiralling ribs broken into small tubercles, each carrying an elongated areole — the narrow, grooved (sulcus-like) areole that gives the genus its name.
The species is best known for its spination, which is variable but tends toward long, dense, and often pectinate (comb-like) spines that can partly obscure the body. Spine colour ranges from pale straw and honey tones to darker brown, sometimes tipped or based in contrasting shades.
Flowers appear from areoles low on the sides of the plant in spring, opening wide and funnel-shaped in intense magenta, purple-red, or crimson, sometimes with a paler throat. Blooms are large relative to the small body and often nearly cover the plant, which is a large part of the species' appeal.
Distribution and habitat
The species is native to Bolivia, centred on the Andean highlands of the Cochabamba region around the town of Tiraque, from which it takes its name. Like other Sulcorebutia, it grows at high elevation in seasonally dry montane grassland and rocky slopes, rooting in gritty, well-drained ground among rocks and low vegetation.
These habitats are marked by cool nights, strong sunlight, and a pronounced dry season, and understanding that rhythm — a warm, moist growing season followed by a cold, dry rest — is the key to growing the plant well.
Cultivation
Sulcorebutia tiraquensis is a rewarding plant for the collector who can give it bright light and a properly dry winter. Grow it in a very free-draining, mostly mineral mix in a pot that gives the roots room, as the species has a tendency to develop a thickened rootstock. Give it strong light with a little shade from the fiercest summer sun to keep the plant compact and the spines well developed.
Water generously through the warm growing months, always letting the mix dry out between waterings, then withhold water entirely as autumn cools. A cold, completely dry winter rest is essential: it hardens the plant, prevents rot, and is what triggers the heavy spring flowering. Plants kept warm and watered through winter tend to etiolate and bloom poorly. See Watering and Repotting for general technique.
Propagation
The species is readily raised from seed, which germinates well on a warm, gritty surface kept humid until the seedlings establish. Because mature plants cluster freely, established offsets can also be removed and rooted — let the cut surface callus for a few days before setting the offset on a barely-moist mineral mix (see Propagation — offsets). Some growers graft seedlings to speed them along, though the species grows well enough on its own roots for most collectors.
Common problems
- Rot — the most common cause of loss, almost always from overwatering, a slow-draining mix, or water left standing during the cold season.
- Etiolation — too little light or a warm, wet winter makes the body soften and stretch and greatly reduces flowering.
- Pests — mealybugs (including root mealybugs, easy to miss on a plant with a thick rootstock) and red spider mites are the usual offenders. See Pests and diseases.
See also
- Sulcorebutia — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Propagation — offsets