ASK AN EXPERT: How do I make sure my Hydrangea blooms blue?

Whether your Hydrangea blooms blue or pink depends on the pH of your soil. Your Hydrangea will bloom blue in a more acidic soil and your Hydrangea will bloom pink in a more alkaline soil.

— Jim W, Prairie Gardens Plant Expert

Make Sure you Have the Right Hydrangea Variety

Whether or not you can change the color of your Hydrangea blooms starts with having the right variety. Only Hydrangea macrophylla Hydrangeas or Big-leaf Hydrangeas have blooms that can change color. These are some of the most common Hydrangea varieties and include the ever-popular Endless Summer Hydrangea.

Measure the PH of your Soil

It’s easy! Use a soil kit to measure the pH of your soil.

  • Less than 7 = Acidity
  • 7 = neutral
  • Greater than 7 = Alkalinity 

Know what pH Your Soil needs to be for the bloom color you want

  • Blue Flowers: pH 5.5 and lower
  • Pink Flowers: pH 6.5 and higher
  • Purple Flowers: pH between 5.5-6.5

Amp up the Soil Acidity for Blue Blooms

To amp up your soil acidity for blue blooms, apply organic acidifiers that include sulfur and sulfate, according to label instructions, and monitor through out the growing season.  

This product on our Solution Wall will do the trick:

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