Gymnocalycium baldianum - Dwarf chin cactus

Gymnocalycium baldianum is a small, floriferous cactus that immediately charms with its well-rounded shape and its red flowers, which are large for such a compact plant. It can be planted in a very well-drained rock garden by the sea, a trough, or a decorative pot kept dry during winter. It is a likeable Argentine species, fairly easy to bring into flower, but tender.

Belonging to the Cactaceae family, Gymnocalycium baldianum is sometimes called spider cactus. The main accepted botanical synonyms for this species are Echinocactus baldianus, Echinocactus sanguiniflorus, Gymnocalycium sanguiniflorum and Gymnocalycium venturianum. It was first described by Spegazzini in 1905 under the name Echinocactus baldianus, then placed in the genus Gymnocalycium in 1925. Its native range lies in northwestern Argentina, mainly in the province of Catamarca. It grows between 500 and 2,000 m above sea level, in dry, rocky, open areas, among mountain lawns and in rock crevices.
It is a long-lived succulent perennial, adapted to the alternation of a moderately moist growing season and a distinctly drier rest period. The plant forms a globose stem slightly depressed at the top, dark green to grey-green, solitary at first, capable of producing a few offshoots over time. The body has 9 to 11 broad midribs, slightly bumpy, bearing areoles with 5 to 7 fine, not very aggressive, grey-brown to light brown thorns. At maturity, the body reaches 10 to 13 cm in diameter and 8 to 10 cm in height.
This species flowers young, which explains its popularity. The flowers appear from May to July, depending on warmth and growing method, near the top. Funnel-shaped, widely open, they measure 4 to 6 cm in diameter in shades of carmine red, magenta red, and sometimes deep pink. The name of this species honours J. Baldi, who helped Spegazzini in his research on Argentine cacti.

Gymnocalycium is hardy down to -4°C in short spells in dry soil. It can only be grown in the open in the mildest regions where winter moisture can be controlled. In open ground, plant it on a stony mound, a rocky slope, or in a rock garden covered with a transparent sheet in winter. In a pot, it thrives in a mix rich in gravel, with long intervals between waterings. 
In the garden or on the terrace, you can combine it with Delosperma Wheels of Wonder Fire, houseleeks Chick Charms® Gold Nugget and 'Commander Hay' and Lewisia cotyledon 'Elise White'. The whole creates a vividly coloured rock plant scene that is very drought tolerant.