slowly growing cactus, densely covered with
incredibly strong twisted spines
Stem: Grey green, compact, globular up to 12 (-15) cm wide 10 cm
tall in cultivation (in nature it is partially underground) with a
slightly concave woolly apex. Will not (usually)
Spines: Long, stout,
eagle claw-shaped, typically-twisted,
up to 4 cm long. Black turning dark grey as they ages.
Flowers: Open petaled, funnel-shaped,
about 4(-7) cm in diameter, 3(-5) cm tall and pinkish in colour. They
grow near the apex. The flowers of Gymnocalycium cardenasianum
have a tough time trying to force themselves through the fierce spines,
and is quite rare to see an open flower because the spines prevent the
flowers from opening properly.
Blooming season: They will bloom at an early age and bloom
sparingly in mid-summer.
Cultivation: Keep this plant almost dry in winter at a minimum
temperature of 0°C. It prefers
growth will stop altogether. The plant tolerates
extremely bright situations (grow it hard, at a high position in the
greenhouse, to try and develop the spines, which are strong and twisted)
but it enjoys some shade during the hottest part of the day in summer.
Propagation: Seeds (seldom produces offsets) or grafting.