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Hydrangea Leaf Spots: Fungal Disease Management

Spots on Hydrangea Leaves: Not Insect Damage

Photos showed spots suggesting fungal leaf spot (likely Cercospora or Anthracnose), not chewing insects. The disease overwinters on dead leaves and stems.

Sanitation First

Remove all dead leaves/stems from plant and ground
Clean up when foliage is dry; bag debris for trash
Prune for better air circulation

Fungicide Program

Apply chlorothalonil, myclobutanil, or copper-based fungicide at bud break and repeat per label (usually 10–14 days) through spring rains. See Extension fact sheet FSA-7570 for details.

Plant Diseases: Crepe Myrtle Yellow Leaf Drop: Cercospora Leaf Spot Management; Rose Bush Pruning: Dealing with Black Stems and Preventing Black Spot; White Residue on Shrubs: Powdery Mildew or Scale Insects?; Reviving Roses After Late Frost and Black Spot in the Pacific Northwest; Chronic Rose Fungal Diseases: Mildew, Black Spot, and Rust Rotation Strategy; Yellow Leaves on 'Flower Carpet' Rose After Wet Spring and Transplanting; Hydrangea Blooms Turning Green/Brown: Fertilizer and pH Issues; Sarracenia Winter Appearance: Why Your Pitcher Plants Look the Way They Do; Preventing Hibiscus Leaf Drop When Bringing Indoors for Winter; Climbing Hydrangeas: Vertical Elegance for Walls and Fences

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