very slowly. In culture R. heliosa is
not among the easiest species to grow, for this reason it is often
grafted. Plants on their own roots are sensitive to overwatering (rot
prone) and need a very good drainage, Keep drier and cool in winter.
Need full sun; Very cold resistant hardy to
-10° C or less for short periods of time.
Propagation: Grafting, since it is difficult
for cuttings to root.
cause of cresting: The cause of cresting is not fully explained.
Biologists disagree as to why some plants grow in this unusual form.
Some speculate that it is a genetic mutation. Others say it is the
result of a lightning strike or freeze damage. But whatever the
stimulus, the growth point of the stem has switched from a geometric
point to a line, which folds and undulates as the crest expands. Though
these crested cacti are somewhat rare (1 in 50,000 or less), cresting
occurs naturally and can be encountered in many other cactus species.