Phlox Sudden Death: Cotton Root Rot, Don't Replant Phlox There

Diagnosis

Rapid wilt → death in days, leaves attached, roots pull easily, brown decayed bark, bronze fungal strands = Cotton Root Rot (Phymatotrichum omnivorum). Soil fungus; active at 82°F+ soil temp.

Why Sudden

Fungus established before symptoms. By wilting, roots extensively invaded.

Action

1. Do not replant phlox there. Fungus persists years.
2. Plant monocots: Daylily, iris, ornamental grasses (resistant).
3. Solarize: Clear plastic 4–6 weeks summer (may reduce).

Prevention

Improve drainage. Avoid organic matter overload (feeds fungus). Raised beds help.

Phlox is highly susceptible. This spot is now a "phlox-free zone." Choose resistant perennials.