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.
Cactus
Cactus flowers are pollinated by insects, birds and bats. None are known to be wind-pollinated and self-pollination occurs in only a very few species; for example the flowers of some species of "Frailea" do not open (cleistogamy). The need to attract pollinators has led to the evolution of pollination syndromes, which are defined as groups of "floral traits, including rewards, associated with the attraction and utilization of a specific group of animals as pollinators."