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.
Desert ecology
Adaptations in xerophytes include resistance to heat and water loss, increased water storage capabilities, and reduced surface area of leaves. One of the most common families of desert plants are the cacti, which are covered in sharp spines or bristles for defence. The bristles on certain cacti also have the ability to reflect sunlight, such as those of the old man cactus. Certain xerophytes, like oleander, feature stomata that are recessed as a form of protection against hot, dry desert winds, which allows the leaves to retain water more effectively. Another unique adaptation can be found in xerophytes like ocotillo, which are "leafless during most of the year, thereby avoiding excessive water loss".