White Discoloration on a Potted Saguaro: Corking or Rot?

A 7-year-old potted saguaro in New England shows whitish corking at the base (normal aging) and a suspicious white spot with black speckling higher up—possible rot from a repotting injury. The plant was watered sparingly (1 tbsp/month) and recently repotted.

Check roots: healthy are fat and whitish; rotted are black/brown with sloughing cortex. The blackened area around a spine suggests a pathogen entry point during transplant. Always wait 3–4 days after repotting before watering to let micro-wounds callous.

If the base is firm, not mushy/hollow, excise the suspicious spot with a sterilized knife to healthy tissue, dust with fungicide, and repot in 2:2:1 sphagnum/perlite/sterilized soil in a pot 1/3 the plant's height. If rot is deep, cut above it and re-root the top.

Saguaros are slow but resilient—worth the effort to save.