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.
Aralia cordata
After seedlings are planted, the soil around the roots should be watered. The surroundings should be concealed with one to three inches of leaf or bark mulch, no higher than the base of the stem. It is useful to water in the morning rather than at night to prevent diseases. To prevent wilting, plants should be watered slowly and enough to achieve deep moisture, achieved by watering, waiting three minutes and watering again. To achieve water-conservation, soaker hoses, drip irrigation, distribution of mulch to prevent water evaporation, and a soil ring around the plant to retain water may be effective. It should be noted that overwatering may cause root issues. Soil drenching is effective in increasing the size of the shoots.