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.
Ferocactus wislizeni
The "fishhook" spines and the armored web of spines enclosing the cactus body are a defense against herbivory. Rarely a mature barrel cactus is found hollowed out by javelina but overall prickly pear experience much higher levels of damage from more species. Barrel cactus spines pose an extreme hazard for handling, penetrating boots and gloves. The roots are quite long but very shallow.