Gymnocalycium, commonly called chin cactus, is a genus of about 70 South American species of cacti. The genus name Gymnocalycium (from Greek, “naked calyx”) refers to the flower buds bearing no hair or spines. Their main area of distribution is Argentina, part of Uruguay, Paraguay, southern Bolivia and part of Brazil. Most species are rather small varying from 4 to 15 centimetres in size. They are popular for their easy flowering habits, and the flowers are generally brightly coloured. Gymnocalycium species are slow to get to a reasonable size. It will offset after a considerable period of time. They are summer growers and needs regular water in summer (but do not over-water). Keep rather dry in winter. They do not like extremely bright situations. Give them some shade during the hottest part of the day. Keep them in low PH compost; otherwise growth will stop altogether. Feed it with a high potassium fertilizer in summer. It is quite frost resistant if kept dry (hardy to -5° C). They are best grown in pots and also do well in rockeries.

Gymnocalycium vatteri is a very variable species. From late spring to summer it bears a profuse amount of flowers that are 4-5 cm long and 4 cm broad. The flowers are a silky white with pink to brownish-red throats. It is a summer growing species that offers no cultivation difficulties. It enjoys part shade to full sun. Water regularly in summer (but do not overwater) keep rather dry in winter. Feed with a high potassium fertilizer in summer. It is quite frost resistant if kept dry and is cold hardy to -5°C.