Eriosyce senilis
| Light | Bright light; will take full sun with acclimatisation |
|---|---|
| Water | Water in the growing season once the mix has dried; keep dry through winter |
| Soil | Gritty, fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep nearly frost-free; tolerates only light frost (to about −4 °C), roughly USDA zones 9b–11 |
| Propagation | Seed |
| Toxicity | Not known to be toxic; the main hazard is the spines |
Eriosyce senilis is a small globular to short-columnar cactus from the semi-arid hills and valleys of north-central Chile, prized for the long, twisted, hair-like spines that veil its body. These soft-looking white to grey spines curl and interlace over the whole plant, so that the vivid magenta-pink flowers appear to push straight out through a fleece of hair. It belongs to the South American genus Eriosyce, and was long known to growers under its former names Neoporteria senilis and Neoporteria nidus.
Description
Eriosyce senilis forms a solitary, roughly spherical stem that lengthens into a short cylinder with age, usually only a few centimetres to around 15 cm tall. The green body is arranged into many low, tuberculate ribs, each areole carrying a dense mass of fine, flexible, hair-like spines. These vary from pure white through soft grey to yellowish, brownish or almost blackish tones between plants, and their twisting, tangled habit is what gives the species its aged, whiskered look and its senilis ("old man") name.
The funnel-shaped flowers open near the crown, typically in spring, in shades of purplish-pink to magenta, often with a paler throat. As in many former Neoporteria, the flowers often only open partway, forming a slender tube that emerges dramatically through the spine cover.
Distribution and habitat
The species is endemic to north-central Chile (Coquimbo, Valparaíso and Metropolitana regions), ranging from around the Elqui valley south to the northern Metropolitana region. It grows on rocky slopes in sclerophyllous scrub and thorny matorral at roughly 350–2000 m altitude, under a Mediterranean-type climate of hot, dry summers and cooler, wetter winters. These origins shape its cultivation needs, in particular its preference for a dry winter rest.
Cultivation
Eriosyce senilis is a rewarding plant for a bright, airy spot, but it resents a wet, stagnant root run. Grow it in a very free-draining, mostly mineral mix and give it strong light; with gradual acclimatisation it tolerates full sun, which keeps the spination dense and the body compact. Water thoroughly once the soil has dried out during the growing season, then allow it to dry again — see Watering for general technique.
Reflecting its Mediterranean-climate origins, the species grows best with a distinct dry winter rest, which also helps it flower. Keep it nearly frost-free and on the dry side through the colder months, and avoid overpotting; a snug pot dries more evenly. Repot only when needed, into fresh gritty mix — see Repotting.
Propagation
The species is normally raised from seed, which germinates well on a warm, humid mineral surface and is the standard way to increase this solitary, non-offsetting cactus. Because it rarely branches, vegetative methods such as offsets or cuttings are seldom relevant, though seedlings are sometimes grafted onto a vigorous rootstock to speed their early growth.
Common problems
- Rot — the commonest cause of loss, almost always from overwatering, a slow-draining mix, or moisture during the winter rest.
- Loss of spine density / etiolation — too little light makes the body stretch and the characteristic hairy spination thin out.
- Pests — mealybugs (white fluff among the spines and roots) and red spider mites can both take hold; see Pests and diseases.
See also
- Eriosyce — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting · Pests and diseases