Eriosyce krausii
| Light | Bright light; strong sun once established, with light shade from harsh midday sun |
|---|---|
| Water | Very sparingly; let the mix dry out completely between waterings, and keep bone dry in winter and during summer dormancy |
| Soil | Extremely gritty, mostly mineral mix with deep drainage for the taproot (see Soil and potting mix) |
| Temperature | Keep above freezing (frost-tender); likes a cool, dry winter rest; roughly USDA zones 10–11 |
| Propagation | Seed |
| Toxicity | Non-toxic to cats and dogs |
Eriosyce krausii is a tiny, geophytic cactus from the Atacama region of northern Chile, anchored by a fat, carrot-like taproot far larger than the small body it feeds. Its diminutive, flattened-globular stem carries neat, comb-like (pectinate) spines pressed close to the surface, and it is one of the miniature Thelocephala-group species that specialist collectors of Eriosyce prize for their scale and character.
Description
Eriosyce krausii is a true miniature. The above-ground body is a small, somewhat flattened globe usually only a few centimetres across, often withdrawing to sit almost flush with the soil surface. Beneath it lies a swollen, tapering taproot that can be several times the volume of the visible plant — a geophytic adaptation that stores water and lets the cactus retract into the ground and vanish during the long dry season.
The spination is one of its charms: short, fine spines arranged in a comb-like (pectinate) pattern that hugs the body, giving the plant a tidy, symmetrical look. Colour ranges through greyish, brownish and dusky greens that blend into the surrounding grit. Funnel-shaped flowers appear from the crown, typically in soft pinkish to yellowish tones, large in proportion to the small body.
Like others in the Thelocephala group, this species has at various times been placed in the segregate genera Thelocephala and Neochilenia; most contemporary treatments fold these into a broadly defined Eriosyce.
Distribution and habitat
The species is native to the Atacama Desert of northern Chile, one of the driest environments on Earth. There it grows in open, stony desert ground, where much of its moisture comes not from rain but from coastal fog (the camanchaca) that drifts inland. Plants sit low among the gravel, often barely detectable, relying on the taproot to see them through prolonged drought.
These are demanding habitats, and wild populations of the miniature Chilean cacti are localised and vulnerable to collection and disturbance. As with the whole cactus family, Eriosyce is listed under CITES Appendix II; nursery-grown, seed-raised plants are the right way to obtain this species, and wild collecting should never be entertained.
Cultivation
Eriosyce krausii is a connoisseur's plant — not difficult in principle, but unforgiving of the conditions that suit ordinary houseplant cacti. The single most important thing is drainage. Because the plant invests so heavily in a fleshy taproot, it must be grown in a deep pot and an extremely gritty, mostly mineral mix so that water flashes through and the root never sits wet.
Give it bright light — it tolerates and appreciates strong sun once acclimatised, with only light shading from the fiercest midday heat. Water sparingly during active growth in the cooler shoulder seasons, always letting the soil dry completely first, and keep the plant bone dry through both the winter and the heat of high summer, when it naturally rests. Overwatering, or a mix that holds moisture around the taproot, is the classic way to lose it to rot. See Watering and Repotting for general technique; when repotting, handle the brittle taproot gently and let any wounds callus before watering.
Many growers keep the Thelocephala-group species on their own roots for the authentic geophytic look, but grafting (see Grafting) is sometimes used to bulk up slow seedlings and to sidestep root-rot worries.
Propagation
Seed is the standard and reliable method. Sow onto a warm, gritty mineral surface and keep humid until germination, then grow the seedlings on hard and dry from an early age. The species does not readily offset, so vegetative increase is uncommon outside of grafting. See Propagation — seed for a full walkthrough.
Common problems
- Rot — by far the leading cause of loss; almost always from overwatering, a moisture-retentive mix, or a shallow pot that keeps the taproot damp. The body softens and discolours, often from below.
- A shrivelled taproot — usually the opposite worry from most cacti: prolonged, total drought (or a root damaged in repotting) rather than everyday under-watering, which this desert species shrugs off.
- Etiolation — too little light makes the normally flat, compact body swell and dome upward, losing its tidy pectinate symmetry.
- Pests — root mealybugs are a particular menace on taprooted species; also watch for red spider mites and ordinary mealybugs (see Pests and diseases).
See also
- Eriosyce — the genus overview
- Grafting · Soil and potting mix · Watering · Repotting · Propagation — seed