Mammillaria magnimamma aka Mexican Pincushion

Mammillaria magnimamma, or Mexican pincushion, belongs to the cactus family, Cactaceae. It comes from Mexico, including the country's central region. Its native habitats include deserts and dry shrubland. This evergreen succulent forms clumps and lives for many years. Gardeners grow it for its rounded stems, spines and flowers.

The green stems have a plump, roughly spherical shape. Raised bumps, called tubercles, cover their surface. White spines and wool grow among these bumps. Individual stems can reach about 1 foot [0.3 metres] tall. The RHS gives a cultivated height range of 0.3–1.6 feet [0.1–0.5 metres]. Clumps can spread 1.6–3.3 feet [0.5–1 metre] across. Plants take about five to ten years to reach maturity. The clump's width can therefore exceed its height by some distance.

Small flowers open near the tops of the stems. Each has a funnel shape. Pink is the usual colour, though red and cream also occur. Spring brings the main bloom, with possible flowers again in late summer. The fruit has a club shape and a dark purplish-red colour. It projects out from the stem. Fruits can reach about 0.07 feet [0.02 metres] long. The seeds are small and brown.

Give this cactus full sun and a sheltered position. Use a potting mix that lets excess water drain away. The RHS lists sandy and loamy soils with a neutral pH. The plant resists drought, but winter wet can cause rot. Keep its potting mix completely dry during winter. A minimum temperature of 5°C suits its cultivation needs. Its RHS hardiness rating is H2, so it needs protection from frost. It can spend summer outdoors where conditions meet these needs.

The RHS recommends this species for containers and patio displays. It also suits city gardens and sheltered courtyards. Its rounded, spiny form provides structure in these settings. Container growing allows a summer outdoor display without leaving it exposed through winter. The plant needs no pruning. Grow new plants from offsets, or sow seed in spring or summer. Check for mealybugs, glasshouse red spider mites and glasshouse whiteflies. These pests can attack plants in cultivation. Good drainage and a dry winter rest help prevent rot.