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
They are desert dwellers and can cope with some frost and intense heat. The typical habitat is hot and very arid, and the plants have adapted to exploit water movement to concentrate their biomass in areas where water is likely to be present. Like "Sclerocactus", "Ferocactus" typically grow in areas where water flows irregularly or depressions where water can accumulate for short periods of time. They are most often found growing along arroyos (washes) where their seeds have been subjected to scarification due to water movement, but they oddly also tend to grow along ridges in spots where depressions have formed and can hold water for some period of time.