Mammillaria bombycina aka Silken Pincushion Cactus

Mammillaria bombycina belongs to the cactus family. Its common name is silken pincushion cactus. It grows wild in Mexico, in Aguascalientes and Jalisco. It lives on mountains, in steep oak woods and on cliffs. Plants grow among fallen leaves on these slopes. These sites lie about 7,680–8,530 feet [2,340–2,600 metres] above sea level. In the past, people broke laws to collect wild plants. This put those plants at risk. LLIFLE says nurseries now raise plants, which has eased this threat.

This succulent stays green all year. It can grow alone or form dense clumps. The RHS lists garden height and spread as 0.3–1.6 feet [0.1–0.5 metres]. Some clumps spread to nearly 3 feet [0.9 metres]. Plants take five to ten years to reach full size. Each stem starts round. It may then form a club or cylinder shape. Its skin can be bright green or grey-green. Raised bumps called tubercles cover each stem. Dense white wool and bristles fill the gaps between them.

Many fine spines spread out from each bump. These radial spines almost hide the green stem skin. They are stiff and white to pale yellow. Longer spines grow at the centre. These have yellow, brown, or reddish tones. The lowest central spine bends down to form a hook. Mature plants bloom in spring. Their flowers form a ring round the crown. Each bloom has a funnel shape. Flowers are pink, carmine, or sometimes white. Each measures about 0.05 feet [0.015 metres] across. The pale green fruits have pink tones.

Grow this cactus under glass in a standard cactus mix. The RHS calls for bright light through cover. It also calls for low moisture in the air. Its guide to where plants grow also lists full sun. Use soil that drains well. Sandy and loamy mixes suit it. It accepts acid, neutral, or alkaline soil. Give moderate amounts of water while it grows. Then keep it almost dry through winter. During growth, give balanced liquid feed every two or three weeks. Its UK hardiness rating is H2. It cannot survive freezing.

Its clumps suit pots and sheltered patio displays. White spines and pink blooms give it its main visual appeal. The RHS suggests a greenhouse or conservatory for shelter. It needs no pruning. Raise new plants from offsets, or sow seed in early spring. Seeds need warmth of 19–24°C. Mealybugs may attack plants, though disease seldom causes trouble. The supplied sources do not show whether it has food uses. Nor do they say whether it is toxic.