Cleistocactus strausii
Silver Torch cactus can thrive in low-nitrogen soil without facing the consequences of low nitrogen. Too much water will make the plant weak and lead to root rot. 
Least Concern. This cactus is locally abundant in its native land and has few local threats to its survival.
This cactus can be propagated by cuttings or seed.
Opuntia aciculata
Like its other cactus relatives, this deciduous and succulent species also has it leaves reduced to spines to reduce excess transpiration, which helps it to survive by conserving water in the hot climate of Texas, in southwestern United States, and North Mexico. This adaptation also helps in defending itself from being consumed by any herbivores there. It has the special ability to propagate from woody or softwood stem cuttings. It can even propagate by cuttings of leaf pads at any time in the growing season, allowing the cut surface to callus over before planting. This cactus can survive healthily and produce good many flowers only if it is fully exposed to the sun. They can also tolerate temperatures from −5 to −12 °C.