Intro: White powder on leaves is usually powdery mildew — common and treatable.
1. Improve airflow
Prune crowded stems.
2. Water the soil, not the leaves
Wet leaves encourage mildew.
3. Remove affected leaves
Stops it spreading.
4. Use a mild fungicide
Garden centres sell safe options.
5. When to prune hard
If mildew returns every year, prune more aggressively in winter.
Summary: Powdery mildew thrives in poor airflow and damp conditions.