How to prune moon cactus

Spring through summer when offsets are small and easy to remove. Snap rootstock side-shoots off by hand as soon as they appear, or cut flush to the stem with a sterile blade. Do not touch the grafted top; it cannot be meaningfully pruned.

As needed — check every few months for rootstock offsets. Moon Cactus (Gymnocalycium mihanovichii) needs no pruning. The brightly coloured top is a mutant graft with no chlorophyll; the green Hylocereus or Cereus rootstock may produce offshoots that should be removed so they don't outcompete the graft. Simply snap or cut rootstock offsets cleanly at their base.

Snap rootstock side-shoots off by hand as soon as they appear, or cut flush to the stem with a sterile blade. Do not touch the grafted top; it cannot be meaningfully pruned.