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.
Echinocereus chisoensis
Because it is self-incompatible, flowers of one cactus require pollen from another individual of the species for fertilization; when plants are rare and spread apart, the likelihood that a pollinator will stop at the plant and deliver the correct pollen is lower. When fruits are successfully produced, they are often taken by jackrabbits and rodents for food. Dry conditions may increase this herbivory and decrease pollinator abundance.