How do I stop blue hydrangea flowers turning pink?
Our Advice
Treat your plants with Hydrangea Colourant from Vitax or from Doff. They contain powdered alum, which enriches the soil with iron and magnesium and encourages the flowers to stay blue. They can be watered into the soil or compost in late-summer just as the flowers are forming in the buds along the stems. Use rain water where possible.
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