Rebutia pygmaea
| Light | Bright light with some direct sun; a cool, airy position suits it best |
|---|---|
| Water | Regularly in the growing season once the mix has dried; keep bone dry through a cold winter rest |
| Soil | Gritty, very free-draining mineral mix |
| Temperature | Loves cool conditions; tolerates light frost if kept dry (roughly USDA zones 8b–10) |
| Propagation | Seed, or removal of offsets from clumping plants |
| Toxicity | Non-toxic to cats and dogs |
Rebutia pygmaea is a tiny, cylindrical, high-altitude cactus from the Andes of southern Bolivia and northern Argentina. Barely a couple of centimetres across, it hunkers down among grass and stones, and in its dry winter rest it shrinks and retracts into the soil until little more than the flattened top is visible. Despite its size it flowers freely, opening comparatively large blooms in shades of pink, red, magenta and orange. It was long placed in the genus Mediolobivia and is still sold under the name Mediolobivia pygmaea, but it is now treated as part of Rebutia.
Description
Rebutia pygmaea forms small, egg-shaped to short-cylindrical bodies usually only 1–3 cm wide and a few centimetres tall. The stems are patterned with low, spiralling ribs broken into small tubercles, each carrying an areole with a few short, comb-like (pectinate) spines pressed close to the body. Colour is variable, from fresh green to a purplish or brownish cast that deepens in strong light and cold. Older plants slowly offset to build up small, low clumps.
The flowers are large in proportion to the plant — funnel-shaped and typically 2–3 cm across — and emerge low down on the sides of the stem rather than from the crown, as is characteristic of Rebutia. Colour ranges widely across the species and its many forms, from soft pink and salmon through vivid red, magenta and orange. Blooms open in spring, usually over a succession of sunny days.
Distribution and habitat
The species is native to the high grasslands and rocky slopes of the Andes in southern Bolivia (around Potosí and Tarija) and adjacent northern Argentina, generally at high elevation. There it grows in thin, gritty soils among tussock grass and rock, exposed to intense sun, wide day-to-night temperature swings, a summer rainy season and a cold, dry winter. During the dry season the plant draws down into the ground, protected from cold and desiccation until the rains return.
R. pygmaea is extremely variable across its range, and over the years many local forms have been described under a long list of names. As with the whole cactus family it is listed under CITES Appendix II, but nursery-raised plants are common and inexpensive.
Cultivation
This is a good beginner's Rebutia and among the easier miniature cacti to flower. Grow it in a gritty, very free-draining mix in a small pot, in bright light with some direct sun. Its one firm requirement is a cool, completely dry winter rest: kept cold and bone dry from autumn to spring, it sets buds reliably and flowers with little fuss; kept warm and watered through winter, it tends to stay shy of blooming and is more prone to rot.
In active growth through spring and summer, water thoroughly once the mix has dried and give it plenty of fresh air — it dislikes stagnant, humid warmth. Because it comes from high, cold habitat, it is hardier than many cacti and will take light frost as long as it is dry. See Watering and Repotting for general technique.
Propagation
Plants raised from seed are easy and show off the species' natural variation in body colour and flower shade. The fine seed germinates readily on a warm, gritty surface kept lightly humid. Clumping specimens can also be increased by detaching rooted offsets and letting the cut surfaces dry before potting them into a mineral mix.
Common problems
- Rot — the main risk, almost always from a wet winter or a slow-draining mix; the stem softens and discolours from the base.
- Reluctance to flower — usually a sign the plant was kept too warm and watered over winter instead of given a cold, dry rest.
- Etiolation — too little light stretches and pales the body and loosens its neat, low form.
- Pests — red spider mites and mealybugs are the usual offenders; check the areoles and root neck.
See also
- Rebutia — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — offsets · Pests and diseases