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.
Pollination
Rain pollination is used by a small percentage of plants. Heavy rain discourages insect pollination and damages unprotected flowers, but can itself disperse pollen of suitably adapted plants, such as "Ranunculus flammula", "Narthecium ossifragum", and "Caltha palustris". In these plants, excess rain drains allowing the floating pollen to come in contact with the stigma. In rain pollination in orchids, the rain allows for the anther cap to be removed, allowing for the pollen to be exposed. After exposure, raindrops causes the pollen to be shot upward, when the stipe pulls them back, and then fall into the cavity of the stigma. Thus, for the orchid "Acampe rigida", this allows the plant to self-pollinate, which is useful when biotic pollinators in the environment have decreased.