My Denmoza rhodacantha
From Argentina, Denmoza is a genus of globular cacti having only two species, Denmoza rhodacantha and Denmoza dulcis pauli. Denmoza range in size from 6 to 12 inches around and gardually grow columnar to 5 feet high as they age. D. rhodacantha has gold or black spines and D dulcis pauli red spines. The flowers are usually red and tubular. Like Cleistocactus, the flowers barely open with only the pistel and stamens visable. The green or reddish fruit are round and split open once ripe.
Grow Denmoza like other cacti in a fast draining mineral based mix. Water regularly in summer and keep dry in winter.
This one is about 8 inches around. It goes in the garden in spring and hopefully will flower for me.