Corking vs. Rot: Diagnosing Brown Base on Tall Cactus

Brown, Hard, Hollow-Sounding Base: Corking or Dry Rot?

A 6–7 foot columnar cactus (possibly Euphorbia) shows brown discoloration from base upward, hard texture, hollow sound when tapped. No watering changes.

Corking (Natural Aging)

Base turns brown, bark-like, firm. Starts at bottom, moves up slowly. Normal for mature cacti and euphorbias.

Dry Rot

Internal desiccation and hollowing; can mimic corking. Distinguished by progressive worsening and eventual instability.

Next Steps

• Leave alone for now.
• In spring, unpot and inspect roots. Dead roots + fully brown stem = rot.
• If roots healthy, it's corking—no action needed.
• If rot, cut off healthy arms, callous, and root them.

ID Note

Close-up of spines needed to confirm cactus vs. Euphorbia.