Q. I follow your column regularly in the LV RJ, but I have not seen an answer to this question: what would make my San Pedro Cactus lose its color? It is becoming pale, please see attached photo.
|San Pedro cactus of the reader|
A. Before I opened your picture I thought it was going to be a lot worse. This is not too bad. I have seen this cactus in much worse condition in Las Vegas.
Not all cacti are the same and cannot be treated the same. The San Pedro cactus, coming from the mountains of South America where the soils are a lot richer and there's much more water, needs different care than cacti native to the Mojave Desert.
This particular cactus will do much better if the soil is well prepared at the time of planting, much like you would prepare the soil for landscape trees and shrubs that are non-desert.
Also irrigating them is different. They have to be watered much more often than cacti native to the Mojave, Sonoran or Chihuahuan deserts.
It will also do better if protected from late afternoon sun. It likes to have lots of direct sunlight but it prefers it during the morning and early afternoon hours.
If you don't keep up with your watering with San Pedro it will begin to yellow or bleach out, scorch around the edges, bleach out and die back. This means the soil that you're using must drain extremely well or you will kill it by not having adequate drainage.
Consider moving it, replanting it with the soil that is Sandy and gravelly and amended with compost. Make sure the area has deep soils that drains easily. Give it is much sun as possible but try to avoid direct sunlight after 2 PM. Water it frequently when temperatures are above 100° F.