Espostoa lanata aka Peruvian Old Man Cactus

Espostoa lanata is a cactus known as Peruvian old man cactus. Cotton ball cactus is another name for this species. It belongs to the cactus family, Cactaceae. Its native range runs from southern Ecuador into Peru. It grows on dry hills and in dry forests. Thorny desert scrub also forms part of its habitat. Many plants grow on the western slopes of the Andes.

This slow-growing cactus forms tall stems and branches with age. Older plants can take on a small tree's shape. Pot-grown plants reach about 1.6–3.3 feet [0.5–1 metre] tall. Their spread is about 0.3–1.6 feet [0.1–0.5 metres]. Wild plants can reach 20–23 feet [6–7 metres]. The stems have rounded ribs beneath a thick woolly cover. RHS records 20–30 ribs, while LLIFLE gives 18–25. White or pale yellow hairs hide many sharp spines. The hairs help hold heat during cold mountain nights. Young spines have brown or reddish tones and turn grey.

White or purple flowers open at night for bat pollination. They grow from a woolly patch along the stem's side. This patch has darker wool and spines than the stem. The funnel-shaped blooms can remain partly hidden among the hairs. Chicago Botanic Garden lists flowering from March through June. LLIFLE places bloom in late spring and early summer. Purplish-red fruits stand out from the wool around them. They have sweet, juicy flesh that people eat raw. Small, glossy black seeds lie inside the fruit.

Grow this cactus in full sun and freely draining compost. RHS lists both sandy and loamy soils as suitable. It accepts acid, neutral, or alkaline soil conditions. Give moderate water while the plant grows in warm months. Keep the compost nearly dry during the winter rest. RHS rates it H2, meaning it should not freeze. Chicago Botanic Garden lists USDA zones 9–10. Useful Tropical Plants reports some brief frost tolerance. Even so, that source recommends avoiding frost when possible.

This plant suits pots, greenhouses, conservatories, and sheltered sunny patios. In suitable climates, gardeners use it in borders or alone. Its upright form and white hairs give year-round interest. Repot plants when their height makes the container top-heavy. RHS says the plant needs no pruning. Mealybugs may attack it, and excess water can cause rot. Both roots and stems can suffer from too much water. People also use its woolly hairs to fill pillows. Useful Tropical Plants reports no known hazards or medicinal uses. The hidden sharp spines still pose a handling risk.