Troubleshooting
Douglas's Phlox problems — and how to fix them
Douglas's Phlox (Phlox douglasii) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Root rot in wet soils
The most frequent cause of plant death; standing water or heavy, poorly drained soil kills the root system quickly — plant in gritty compost or a raised, sloping bed.
Powdery mildew
White, powdery coating on leaves in humid or shaded conditions; prune back after flowering to open up the canopy and improve airflow.
Spider mites
Stippled, yellowing foliage in hot, dry summers signals mite activity; increase irrigation and treat with insecticidal soap or a miticide if severe.
Prevent douglas's phlox problems before they start
Most douglas's phlox issues are care-mismatch, not bad luck. Dial in the basics:
Douglas's Phlox problems — FAQ
Why is my douglas's phlox root rot in wet soils?
The most frequent cause of plant death; standing water or heavy, poorly drained soil kills the root system quickly — plant in gritty compost or a raised, sloping bed.
Why is my douglas's phlox powdery mildew?
White, powdery coating on leaves in humid or shaded conditions; prune back after flowering to open up the canopy and improve airflow.
Why is my douglas's phlox spider mites?
Stippled, yellowing foliage in hot, dry summers signals mite activity; increase irrigation and treat with insecticidal soap or a miticide if severe.