Copiapoa krainziana
| Light | Bright light with some protection from the harshest afternoon sun |
|---|---|
| Water | Sparingly; allow to dry fully between waterings, kept dry in winter |
| Soil | Very free-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; frost-tender, USDA zones 9b–11 |
| Propagation | Seed; offsets from clustering plants |
| Toxicity | Non-toxic to cats and dogs |
Copiapoa krainziana is a slow-growing globular cactus from the coastal desert of northern Chile, prized among collectors for its unusual armament of numerous fine, white, flexible bristle-like spines over a grey-green body. This soft, hair-like spination — quite unlike the stiff dark spines of many of its relatives — makes it one of the most distinctive and desirable species in the genus Copiapoa.
Description
Copiapoa krainziana forms a rounded to shortly cylindrical body that in time clusters from the base into low mounds. The skin is a soft grey-green, often with a subtle waxy or greyish cast typical of the genus. Its most striking feature is the spination: the areoles carry many thin, flexible, bristle-like spines that are usually whitish to pale grey, curving and tangling together to give the plant a soft, almost woolly or hairy look. Spine density and colour vary a good deal between individual plants, which is part of the species' appeal to growers.
Flowers appear from the woolly crown, opening yellow and funnel-shaped in the warmer months. As with most Copiapoa, the wool at the apex becomes denser on mature plants, cradling the buds and flowers.
Distribution and habitat
The species is native to a small area of the Atacama Desert of northern Chile, one of the driest places on Earth. Like other members of the genus, it grows on arid coastal hills and slopes where measurable rain may fall only rarely and much of the plants' moisture comes from camanchaca — the coastal fog that rolls in off the Pacific. Plants root in mineral, gritty ground among rock, fully exposed to strong light and drying wind.
Because of its restricted range and its popularity with collectors, wild Copiapoa populations are vulnerable to illegal collection and habitat pressure. Like the whole cactus family, Copiapoa is listed under CITES, so only nursery-propagated plants should be bought and traded; collecting from habitat is both harmful and illegal.
Cultivation
Copiapoa krainziana is a plant for the patient grower — it is naturally very slow. Grow it in a very free-draining, mostly mineral mix in a pot that drains freely, and give it the brightest light you can, with just a little protection from the most intense afternoon sun under glass. Good airflow helps keep the body firm and the fine spines clean.
Water thoroughly only when the soil has dried out completely during the growing season, then allow it to dry again; err on the side of dryness, as the roots resent staying wet. Keep the plant completely dry and cool through winter to prevent rot and encourage flowering. Coming from a fog desert, it appreciates atmospheric humidity far more than root moisture. See Watering and Repotting for general technique.
Slow-growing collector plants of this species are sometimes grafted onto a vigorous rootstock to speed them along, though many growers prefer the tighter, more characterful growth of plants on their own roots.
Propagation
Seed is the usual method, and raising Copiapoa from seed — while slow — is very rewarding; sow onto a warm, mineral surface kept lightly humid until germination, then grow the seedlings on hard and bright. Clustering plants can also be increased by removing rooted offsets, which are potted up into the same gritty mix once any cut surface has callused. See Propagation — seed and Propagation — offsets for full walkthroughs.
Common problems
- Rot — the commonest cause of loss, almost always from overwatering or a mix that holds too much moisture; the body softens and discolours from the base or crown.
- Etiolation — too little light makes the body pale and swell out of its natural squat shape and can leave the spines sparse and weak.
- Pests — red spider mites (fine webbing and bronzed skin) and mealybugs (white fluff tucked among the spines and wool) are the usual offenders. See Pests and diseases.
- Impatience — this is a slow species; sudden lush growth is usually a sign of overwatering or overfeeding rather than success.
See also
- Copiapoa — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Propagation — offsets · Repotting · Pests and diseases