– Gymnocalycium cardenasianum (2013)

By Ann Tansey (June 2013)

Gymnocalycium cardenasianum is one of the best gymnos. It has incredibly strong, curved spines, although it is slow-growing. It is named for mycologist and botanist Professor M. Cardenas. The origin for this cactus is Bolivia (Tarija).

G. cardenasianum grows as a solitary plant at a slow pace. The step is compact, gray green and globular – up to 15 centimeters wide and 10 centimeters tall in cultivation. In nature, the plants grow partially underground. They have a slightly concave, woolly apex, and as a rule will not offset.

The spines are striking. They are long and shaped like an eagle’s claw, usually twisted up to 6 centimeters long. The color is usually white or pale brown. The pink flowers have open petals about 4 to 7 centimeters in diameter and 3 to 5 centimeters tall. The flowers grow near the apex. At blooming time, the flowers have a difficult time trying to poke through the spines. It is rare to see an open flower because of the multitude of close spines.

G. cardenasianum will bloom early and sparingly in mid-summer. The length of time from seed to flowering is five to six years. The result of the spination will vary according to the locality of the parent plant.

Gymnocalyciums, commonly called chin cacti, reflect a genus of about 70 South American species. They are easy to grow. The cacti must not have temperatures less than 50 degrees F from September through May. These desert cacti need to be kept in a warm and sunny position, avoiding direct sunlight. From May to September, they benefit from being out of doors, where they can receive full sun gradually.

Generally fertilize G. cardenasianum with cactus fertilizer at half strength. Repotting can be done an average of every three years, unless roots are crowded. Use pots that are about 2 inches bigger than the present size. Use a mix of coir combined with rock or perlite.