We have had a lot of rain this winter in Southern CA. My beautiful organ pipe cactus has developed a large split in the outer skin. Will it heal over? Can I save it?
Likely, it will be ok. You might want to treat with a fungicide just in case, though. Keep an eye out for spreading. If it starts to spread, then I would cut that whole arm off and treat that with fungicide, as well.
This article will offer more care information:
There are multiple small limbs sometimes two and three coming off a larger limb mostly near the ground. We have a small yard and I would like to know if these could be trimmed without harming the cactus.
Organ pipe cactus should not need pruning so unnecessary cutting on the cactus will leave it vulnerable to insect or disease invasion. Here is more on its care:
https://www.public.asu.edu/~camartin/plants/Plant%20html%20files/stenocereusthurberi.html