How to Fertilize Hydrangeas to Change Flower Color
For blue hydrangeas: lower soil pH below 5.5 with sulfur, use acidifying fertilizer like Holly-tone (4-3-4), and apply aluminum sulfate (1 tbsp per gallon water) in spring. For pink: raise pH above 6.0 with lime and use balanced 10-10-10. Avoid high-phosphorus fertilizers for blue, phosphorus locks out the aluminum that creates blue pigment. White hydrangeas cannot change color.
What You Need to Know
For blue hydrangeas: lower soil pH below 5.5 with sulfur, use acidifying fertilizer like Holly-tone (4-3-4), and apply aluminum sulfate (1 tbsp per gallon water) in spring. For pink: raise pH above 6.0 with lime and use balanced 10-10-10. Avoid high-phosphorus fertilizers for blue, phosphorus locks out the aluminum that creates blue pigment
White hydrangeas cannot change color.
For personalized recommendations based on your specific garden size and fertilizer, use our fertilizer calculator.
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