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When to Fertilize Hydrangeas for Best Blooms

Penn State Extension

Fertilize hydrangeas three times per year: March (as new growth emerges), May (during active growth), and July (last application). Do not fertilize after August, late feeding promotes tender growth that will be damaged by frost. Apply aluminum sulfate for blue color in early spring before flower buds develop. Slow-release fertilizer applied once in spring is an alternative to three lighter applications.

What You Need to Know

Fertilize hydrangeas three times per year: March (as new growth emerges), May (during active growth), and July (last application). Do not fertilize after August, late feeding promotes tender growth that will be damaged by frost. Apply aluminum sulfate for blue color in early spring before flower buds develop

Slow-release fertilizer applied once in spring is an alternative to three lighter applications.

For personalized recommendations based on your specific garden size and fertilizer, use our fertilizer calculator.

Sources

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