Troubleshooting
Rosemary problems — and how to fix them
Rosemary (Rosmarinus officinalis) 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 from overwatering
The most common problem. Leaves yellow, then the plant collapses from the base. Ensure excellent drainage, avoid saucers under pots, and water only when soil is dry. There is no recovery from severe root rot — prevention is essential.
Powdery mildew
White powdery patches appear on leaves in damp, humid conditions with poor airflow. Improve drainage and air circulation. Remove affected shoots and avoid wetting foliage when watering.
Frost dieback
In zones 7 and below, stems die back in hard frosts. Mulch the root zone in autumn, avoid pruning in autumn (which stimulates frost-tender growth), and site plants against a south-facing wall for extra warmth.
Prevent rosemary problems before they start
Most rosemary issues are care-mismatch, not bad luck. Dial in the basics:
Rosemary varieties: common problems
Looking for rosemary in general rather than its problems? Read the full rosemary care guide — light, water, soil and feeding.
Rosemary problems — FAQ
Why is my rosemary root rot from overwatering?
The most common problem. Leaves yellow, then the plant collapses from the base. Ensure excellent drainage, avoid saucers under pots, and water only when soil is dry. There is no recovery from severe root rot — prevention is essential.
Why is my rosemary powdery mildew?
White powdery patches appear on leaves in damp, humid conditions with poor airflow. Improve drainage and air circulation. Remove affected shoots and avoid wetting foliage when watering.
Why is my rosemary frost dieback?
In zones 7 and below, stems die back in hard frosts. Mulch the root zone in autumn, avoid pruning in autumn (which stimulates frost-tender growth), and site plants against a south-facing wall for extra warmth.