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.
Opuntia ficus-indica
The cattle industry of the Southwest United States has begun to cultivate "O. ficus-indica" as a fresh source of feed for cattle. The cactus is grown both as a feed source and a boundary fence. Cattle avoid the sharp spines of the cactus and do not stray from an area enclosed by it. The cactus pads are low in dry matter and crude protein, but useful as a supplement in drought conditions. In addition to the food value, the moisture content adequately eliminates watering the cattle and the human effort in achieving that chore.