How to prune saguaro cactus

Spring or early summer, only if rot is actively spreading. Using a sterilized saw, cut into healthy tissue above the rot line. Dust the wound with powdered sulfur and keep the plant in a dry, warm, well-ventilated spot. Do not water for 2–4 weeks. Monitor for further spread. Note: in the wild, saguaro wounds form callous 'boots' naturally.

Very rarely — only when active rot demands surgical removal. Saguaro Cactus (Carnegiea gigantea) grown as a houseplant or container specimen must never be pruned for size or shape — it grows extremely slowly and any cut causes permanent scarring. Remove only arms or sections that show active, spreading rot. Healthy tissue should never be trimmed under any circumstances.

Using a sterilized saw, cut into healthy tissue above the rot line. Dust the wound with powdered sulfur and keep the plant in a dry, warm, well-ventilated spot. Do not water for 2–4 weeks. Monitor for further spread. Note: in the wild, saguaro wounds form callous 'boots' naturally.