Hydrangea Brown Leaf Spots: Cercospora vs. Anthracnose

Hydrangea in western NC has recurring brown leaf spots for 4 years; blooms well.

Two Main Diseases

• Cercospora leaf spot: Many small spots; may coalesce into large dead areas.
• Anthracnose: Larger spots, often target-shaped (concentric rings).

Diagnosis and Management

Compare symptoms to this guide (images included). Management for both:

• Remove/destroy infected leaves.
• Improve air flow.
• Avoid overhead watering.
• Spring fungicide (chlorothalonil, mancozeb) if severe.

Expert insight provided by Steve.