Eriosyce paucicostata
| Light | Bright light with good airflow; some protection from the fiercest summer sun |
|---|---|
| Water | Sparingly; allow to dry fully between waterings, keep dry through winter |
| Soil | Very free-draining, gritty mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; roughly USDA zones 9–11 |
| Propagation | Seed |
| Toxicity | Non-toxic to cats and dogs |
Eriosyce paucicostata is a small, globular to shortly columnar cactus from the arid coast and foothills of northern Chile, prized among collectors for its cool grey-green skin, few prominent ribs and dark, contrasting spines. In spring and summer it opens funnel-shaped flowers in shades of cream through to soft pink at the crown, and it remains a firm favourite among growers of the plants once separated into the genus Neochilenia.
Description
Eriosyce paucicostata is a solitary plant forming a firm, rounded body that elongates and becomes shortly columnar with age, a few centimetres across. As the species name suggests, it carries relatively few ribs — usually prominent and somewhat notched into tubercles — over a matte grey-green to bluish-green epidermis that helps it reflect harsh light. The colouring can deepen to purplish or bronze tones when the plant is grown hard and dry.
The areoles bear stiff, dark spines that stand out sharply against the pale body; the spines are thickish, blackish when young and fading to silvery grey with age. Flowers emerge from the woolly crown, are broadly funnel-shaped, and range from creamy and pale yellowish to a delicate pink flush. They are followed by small fruits containing black seed.
Distribution and habitat
The species is native to northern Chile, where it grows in the coastal desert and adjacent foothills of the Antofagasta region, extending south towards Caldera. Plants root in rocky, mineral-poor ground and endure long rainless periods, drawing much of their moisture from coastal fog (the camanchaca). In habitat they often sit low among stones, contracting during drought so that little more than the spined crown is visible.
Like the whole cactus family, Eriosyce is listed under CITES Appendix II, so international trade is regulated. Nursery-raised, seed-grown plants are the norm in cultivation and are entirely legal to own and trade; wild collecting is not.
Cultivation
Eriosyce paucicostata is a rewarding but water-sensitive plant, and overwatering is by far the commonest cause of loss. Grow it in a very free-draining, mostly mineral mix in a snug pot, giving bright light and generous airflow. Water thoroughly only when the soil has dried right out, then hold off; keep the plant completely dry and cool through winter to prevent rot and to encourage flowering.
These desert plants dislike sitting in damp, rich compost. Many growers keep them slightly under-potted and add extra grit or pumice to speed drainage. See Watering and Repotting for general technique. Some collectors graft slow or difficult seedlings to build size quickly, though the species grows acceptably on its own roots given patience.
Propagation
Seed is the standard and most reliable method. Sow onto a warm, mineral surface kept humid until germination, then grow the seedlings on hard and bright. Because the species is usually solitary, offsets for vegetative propagation are seldom available. See Propagation — seed for a full walkthrough.
Common problems
- Rot — nearly always from overwatering or a slow-draining mix; the body softens and discolours from the base or crown.
- Etiolation — too little light makes the body pale, soft and unnaturally elongated, losing its compact form and rib definition.
- Pests — red spider mites (fine webbing, bronzed skin) and mealybugs (white fluff in the areoles and among the roots) are the usual offenders. See Pests and diseases.
See also
- Eriosyce — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting