Austrocylindropuntia
Austrocylindropuntia is a small genus of cylindrical-stemmed opuntioid cacti from the Andes of South America. The name means "southern Cylindropuntia", and the genus is set apart from its northern relatives chiefly by its spines, which lack the papery, deciduous sheaths that give true chollas their distinctive look. These are tough Andean plants ranging from ground-hugging cushions to substantial shrubs and small "trees", and several of the vigorous lowland-valley species are familiar in cultivation as easy, forgiving beginner cacti.
Description
Members of Austrocylindropuntia have segmented, cylindrical (terete) stems rather than the flattened pads of Opuntia. Like all opuntioids they bear areoles armed with glochids — tiny, barbed, easily detached bristles that lodge in skin — so the plants should always be handled with care. The true spines are variable: some species are nearly spineless, while others carry long, fine, sometimes hair-like spines. Crucially, these spines have no papery sheath, the single most reliable feature separating this genus from Cylindropuntia.
A further distinctive trait is the presence of persistent, small, cylindrical or awl-shaped succulent leaves on new growth — a primitive feature retained from the opuntioid ancestors and more conspicuous here than in most other cacti. The leaves are usually shed as the segments mature. Flowers are showy and typically red, orange, pink or yellow, opening on the stem tips, and are followed by fleshy, often spineless fruit.
Distribution
The genus is South American and strongly Andean, centred on Peru, Bolivia, Ecuador, Argentina and Chile. Plants grow at a wide range of elevations, from valley scrub up into high-altitude puna grassland, where they endure intense sun, dramatic day-to-night temperature swings and, at altitude, hard overnight frosts. This montane origin is the reason several high-altitude species tolerate cold far better than lowland cacti.
Notable species
- Austrocylindropuntia subulata — the Eve's needle cactus, a tall, shrubby to tree-like grower with prominent, long, persistent subulate (awl-shaped) leaves; widely grown and often used as a hedge or grafting stock.
- Austrocylindropuntia cylindrica — an erect, slender-stemmed species with neat cylindrical segments and small leaves, popular as an easy houseplant.
- Austrocylindropuntia vestita — the old man opuntia, clothed in long white hairs and bearing deep red flowers; a compact, characterful favourite.
- Austrocylindropuntia floccosa — a high-altitude Andean species forming dense, mounded, woolly cushions in habitat, adapted to intense cold and sun.
- Austrocylindropuntia shaferi — a low, clumping species with slender segments and dark, hairy spination.
Cultivation
The vigorous lowland-valley species are among the most forgiving cacti to grow, though the high-altitude cushion-formers are slower and considerably more demanding. They ask for bright light — the more sun the better, which keeps growth compact and encourages flowering — and a fast-draining, mostly mineral mix. Water freely during the warm growing season once the soil has dried, then keep them much drier and cooler through winter; a dry winter rest both prevents rot and improves flowering. Some high-altitude species are notably cold-tolerant and will take frost if kept dry, but the popular fast-growing species such as Austrocylindropuntia subulata are frost-tender; hardiness varies greatly by species and provenance, so protect from freezing unless you know a plant's limits.
Growth in the shrubby species is often vigorous, and they can be pruned to shape or size; cuttings root easily. See Watering and Repotting for general technique, and always wear gloves — the glochids are the main hazard when handling or potting these plants.
In cultivation and hobby notes
Austrocylindropuntia is valued as much for its usefulness as its looks. The stronger-growing species, especially Austrocylindropuntia subulata, are commonly used as vigorous rootstock for grafting slow or tender cacti, and its cristate (crested) and monstrose forms are collectors' items in their own right. The hairy species such as Austrocylindropuntia vestita are grown for their soft white "old man" clothing. Because most root so readily from cuttings, plants are inexpensive and widely shared among growers.
Propagation
Propagation is easiest from stem segments. Detach a segment, allow the cut end to callus for several days in a dry, shaded spot, then set it in a gritty mix and water sparingly until roots form — see Propagation — cuttings. Seed is also viable but slower and less commonly used by hobbyists (see Propagation — seed).
Common problems
- Rot — from overwatering, poor drainage or cold, wet winter conditions; stems soften and discolour.
- Etiolation — too little light causes weak, thin, over-stretched growth.
- Glochids — not a plant problem but a grower one: the barbed bristles detach at a touch and are hard to remove from skin, so handle with gloves or folded paper.
- Pests — mealybugs (white fluff in areoles and roots) and scale are the usual offenders; see Pests and diseases.
See also
- Cylindropuntia — the northern chollas, distinguished by papery spine sheaths
- Opuntia — the flat-padded prickly pears
- Grafting · Soil and potting mix · Watering · Propagation — cuttings