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.
Arrojadoa
Source :.
These tropical cacti are not very easy to grow. With their snake-like growth, they are ideal cactus for hanging baskets. They are growing relatively rapidly in good conditions. It multiplies more by seeds than by cuttings. It grows best on slightly humid soil and with plenty of watering from spring to autumn. In winter it should be left without water and at a minimal temperature of 10 °C.