Complex Decline in a 6-Year Snake Plant (Sansevieria): Rot, Pot-Binding, and Pup Rescue

A 6-year Sansevieria shows yellowing from 1" below tips (wrinkled, blistered), black mold near tips, black spots. Roots brown-orange, not slimy. Anti-fungal rub didn't help. Same pot 6 years, no fertilizer, water 2x/month, window no direct sun, England, cold winter. Pup growth increased last month. Owner fears overwatering after Christmas absence. Diagnosis: dry rot (shrivel/blister) or wet rot. Winter is active season for Sansevieria—explains pup growth. Action: 1) Remove damaged leaves—destroy. If they pull easily, basal rot exists. 2) Check roots: should be whitish; rhizome darker. No soft/brown roots. 3) Separate pups (inspect them), pot small in 1:1 perlite/peat, fungicide/bleach dip (1:9), no water 1 week. 4) Mother: remove dead roots, loosen bound roots (nutrient exhaustion), rinse, bleach dip, sit bare-root 1 week, dust fungicide. 5) Repot in smaller deep pot, wait 4–5 days, water by soil feel (moist=wait, dry=water). Sansevieria prefers slight moisture. Isolate mother, destroy soil. Pups have good odds; mother is iffy. Resilient species—don't quit gardening.