How to prune stenocactus multicostatus

Only if damaged or rotting tissue is present — any time of year. If rot appears, cut back to healthy green tissue with a sterilised sharp knife, dust the wound with powdered sulphur or cinnamon, and allow it to dry completely before watering resumes.

Rarely — only when damage or rot is present. Stenocactus multicostatus (brain cactus) does not need pruning. Its tightly ribbed, globular form is self-contained with no offshoots or stems to manage. Remove any dead or damaged spines and tissue with a sterile tool if rot occurs, but routine pruning is unnecessary and can harm the plant.

If rot appears, cut back to healthy green tissue with a sterilised sharp knife, dust the wound with powdered sulphur or cinnamon, and allow it to dry completely before watering resumes.