Cleistocactus strausii
As a houseplant, the Silver Torch cactus is an easy to take care of so long as over-watering is avoided. To naturally simulate the porous effects of the sand in its native habitat, it's important to ensure that excess water will not pool in the soil, causing the roots to become water logged.
This plant’s native habitat does not have winter, but when temperatures drop to the low twenties, it can exhibit signs of tip frost. 
The Silver Torch cactus is most susceptible to 
mealybugs 
and spider mite.
Ferocactus
"Ferocactus" have very shallow root systems and are easily uprooted during flash floods. The "fishhook" spines and the armored web of spines enclosing the cactus body in many species of this genus are adaptations which allow the plant to move to more favorable locations. The seeds germinate in areas where water movement occurs or in areas where standing water accumulates for some period of time, and during flash floods, the hooked spines allow the plants to be caught on waterborne debris, uprooted and carried to areas where water tends to accumulate.