Parodia buiningii
| Light | Bright light; a little shade from the fiercest summer sun |
|---|---|
| Water | Regularly in the growing season, allowing the mix to dry between waterings; keep dry and cool in winter |
| Soil | Fast-draining, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; roughly USDA zones 9b–11 |
| Propagation | Seed (primary); occasionally offsets |
| Toxicity | Non-toxic to cats and dogs |
Parodia buiningii is a small, flat-topped South American cactus prized by collectors for its crisp, sharp-edged ribs, its fresh bright-green body, and its large, glossy yellow flowers. Long grown under the name Notocactus buiningii, it is a compact, mostly solitary plant whose geometric outline and stiff, cross-set spines make it one of the most distinctive members of the genus Parodia.
Description
Parodia buiningii forms a solitary, flattened to slightly depressed globe, typically only a few centimetres to around 10 cm across, with a broad flat top. The body is a striking fresh, bright green and is divided into relatively few sharp, prominently angled ribs — usually around sixteen — that give the plant a clean, faceted, almost architectural outline unusual among the softer-ribbed Parodia.
Woolly areoles along the sharp rib edges carry a few straight, stiff spines — yellowish to straw-coloured with dark brown bases, the central ones set in a distinctive cross and up to a couple of centimetres long — rather than forming a dense armour. In the growing season, large glossy yellow flowers open from the woolly crown, wide and shining. Bristly fruits follow, holding fine dark seed.
Distribution and habitat
The species comes from a limited area of southern South America, in the grassland country of Uruguay and the neighbouring Brazilian state of Rio Grande do Sul. It grows on rocky and gritty outcrops among grasses and low vegetation, where the surrounding plants give it a little shade and where rain falls more regularly through the growing season than in true desert habitats.
Like all cacti, Parodia buiningii is listed under CITES Appendix II, and wild plants can be vulnerable to collection and land-use change. Nursery-propagated plants are readily available and are the only ones that should be bought or traded.
Cultivation
Parodia buiningii is a rewarding grower that is a little more thirsty in summer than many desert cacti, reflecting its grassland origins. Grow it in a free-draining, mostly mineral mix in bright light, with just a little protection from the most intense afternoon sun to keep the green body from scorching.
Water thoroughly through the warm months once the mix has dried, then ease off as autumn arrives. A cool, completely dry winter rest is important: it hardens the plant, encourages spring flowering and helps prevent rot, which — as with most cacti — is the main risk from overwatering or a heavy, water-holding mix. See Watering and Repotting for general technique.
Propagation
Seed is the usual method. The fine seed germinates well on a warm, damp mineral surface kept humid until the seedlings establish; see Propagation — seed for a full walkthrough. The species is generally solitary but will occasionally produce offsets, which can be removed and rooted once they have formed a small base — see Propagation — offsets. Slow or difficult seedlings are sometimes grafted to build size more quickly before being grown on.
Common problems
- Rot — usually from overwatering, a slow-draining mix, or water left standing in winter; the plant softens and discolours from the base or crown.
- Scorch — sudden strong sun on the green skin can leave pale, bleached patches; increase light gradually.
- Etiolation — too little light makes the body pale and dome upward, blurring the crisp ribs.
- Pests — mealybugs (white fluff in the areoles and on the roots) and red spider mites (fine webbing, bronzed skin) are the usual culprits. See Pests and diseases.
See also
- Parodia — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Propagation — offsets