Gymnocalycium bruchii

Gymnocalycium bruchii also goes by Bruch's chin cactus. It belongs to Cactaceae, the cactus family. It comes from Córdoba and San Luis in Argentina. Kew places it in a subtropical climate. This small succulent grows in clumps, not one tall stem. It suits pots and groups of houseplants. It also suits space under glass. The RHS lists it for patio pots and sheltered sites.

The stems have ribs and a round shape. Some stems have a flatter shape. They range from dark green to blue-green. White radial spines spread out to form a bristly cover. These spines may be straight or curved. Each stem grows about 0.2 feet [0.06 metres] tall. The RHS gives its mature height as 0.33 feet [0.1 metres]. It gives the same size for its spread. LLIFLE says older clumps reach 0.49 feet [0.15 metres] across. The plant keeps its green growth all year.

The flowers open in a funnel or bell shape. The RHS lists pale pink blooms in early summer. Each flower can span about 0.15 feet [0.045 metres]. LLIFLE lists lavender-white blooms that open in early spring. These reach 0.2 feet [0.06 metres] across. LLIFLE also notes green fruit once the blooms fade. The sources differ on flower colour, size, and season. LLIFLE says the species varies and grows slowly. The RHS says it takes two to five years to reach full size.

Grow it in cactus compost that drains well. The RHS lists both sand and loam as suitable soils. It accepts acid, neutral, or alkaline soil. Give it strong light and shade from the hottest sun. The RHS advises a sheltered spot facing south or west. Water well in spring and summer. Use a low-nitrogen feed once a month in those seasons. The RHS says it can cope with drought. It still advises watering while the plant grows.

The RHS gives it a UK hardiness rating of H2. It can cope with cool air, but not frost. A greenhouse, conservatory, or pot indoors fits that rating. It needs no pruning. The RHS reports few disease problems. Mealybugs may still be a pest. To grow more plants, remove offsets, or side shoots, in spring. You can also sow seeds in late winter or early spring. Keep seed sowings at 19–24°C.