Gymnocalycium pflanzii aka Chin Cactus

Gymnocalycium pflanzii is a small cactus in the Cactaceae family. Gardeners also call it Pflanze's chin cactus. Its native range spans Bolivia and Paraguay, with LLIFLE also recording northern Argentina. It grows in rocky places and sandy soils near dry Chaco woodland. Some plants grow beneath thorny shrubs or partly buried in soil. Wild plants occur at heights of 1,640–8,200 feet [500–2,500 metres].

The plant grows alone or slowly forms a clump. Its rounded stem has a flattened top with a woolly hollow. Garden plants reach about 0.33–0.49 feet [0.10–0.15 metres] tall. Stems span about 0.33–0.49 feet [0.10–0.15 metres], sometimes reaching 0.82 feet [0.25 metres] across. The skin ranges from pale green to olive and looks velvety. Strong sun can bring out orange and purple tones. Ten to twelve broad ribs divide into rounded tubercles. Oval areoles carry pale wool, which darkens with age. Stiff spines curve back toward the stem. They start dark, then fade to pale shades with dark tips.

Flowers open near the stem top during summer. Even young plants can bloom. Each funnel-shaped flower measures about 0.15–0.16 feet [0.045–0.05 metres] across. White petals surround a pink to purple-red throat. The flowers also have yellow pollen. Round fruits turn deep red as they ripen. They measure about 0.07 feet [0.02 metres] across and contain red flesh. The tiny seeds have smooth, shiny, reddish coats. These fruit details do not establish that the plant is edible.

Grow this cactus in cactus compost that drains well. RHS lists both sandy and loamy soils across a broad pH range. Give it bright light, but shade it from hot sun. Water well during spring and summer. Apply a low-nitrogen feed each month during this growing season. RHS rates it H2: it tolerates cool weather but not freezing. Its drought tolerance does not replace watering during active growth. Plants take roughly two to five years to mature.

Its small size suits pots, greenhouses, conservatories, and indoor displays. RHS also lists patio containers among its uses. It needs no pruning, and growers can raise it from seed. RHS describes its care as easy and reports few disease problems. Mealybugs can attack it. In the wild, farming and goat grazing cause local pressures. LLIFLE describes these threats as minor across its broad range. The supplied sources do not establish its safety for people or pets.