Austrocylindropuntia vestita aka Cotton Cacti

Austrocylindropuntia vestita is a shrubby cactus in the Cactaceae family. Its native range runs from Bolivia to northwestern Argentina. It grows in rocky grasslands high in the mountains. Records place it at 7,874–11,811 feet [2,400–3,600 metres] above sea level. Kew also links it with deserts and dry shrubland. The RHS lists Opuntia vestita as a synonym. English names include old man opuntia and cotton coral cactus.

This cactus forms slim, upright stems with a thick white coat. Branches grow from the base and near the stem tips. The stems reach almost 2 feet [0.6 metres] tall. Each measures about 0.07–0.10 feet [0.02–0.03 metres] across. Long, fine hairs cover the branches and hide much of their surface. A few thin white spines grow among these hairs. The spines reach about 0.03 feet [0.01 metres] long. The species name refers to this coat of hair.

The leaves are narrow and awl-shaped, a form called subulate. They fall off, though regular watering can keep them from spring through autumn. Flowers do not appear reliably, so blooms cannot be counted on. When they form, they grow at the stem tips. Their colour ranges from deep red to violet. They reach about 0.08 feet [0.025 metres] across. Dense hairs also cover the pericarpel, which surrounds the ovary. This part has fewer spines than the stems. LLIFLE describes the fruit of this species as sterile.

In cultivation, give the plant full sun or some light shade. Use a mineral-rich potting mix that drains very freely. Water during growth once the soil has dried. Keep the plant dry through winter, and guard against severe frost. Its mountain origin does not mean it tolerates every cold garden. The evidence gives no firm hardiness zone. It dislikes hot, enclosed summer conditions and needs good airflow.

Root rot is a key risk, so watering needs care. Cuttings root readily and offer a practical way to raise plants. Seeds are scarce and very hard to germinate. The white hair and upright branches give the plant its distinct appearance. In the wild, LLIFLE reports a broad distribution and abundant plants. It identifies no major threats to the species.