January 8, 2020 Melisse & Co.

Melisse & Co. - How to Change the Color on your Hydrangeas

How to Change the Color on your Hydrangeas

To begin, use a soil test kit to determine the current pH levels of your soil. This may seem complicated, but it is actually a pretty simple process. All soil has a pH value which measures the acidity or alkalinity. The pH scale is from 0 to 14; 7 is neutral. Soil pH values of less than 7 indicate degrees of acidity. Soil pH values greater than 7 indicate degrees of alkalinity.

Next, determine whether you would like your hydrangea blooms to be pink, purple, blue or a combination of blue and pink. Then adjust the pH of your soil from it's current pH level to reflect the respective color you would like. A good rule of thumb to follow is the more acidic, the darker the flower. For your convenience, below is a list of hydrangea bloom colours and the pH levels to achieve those colors.

Blue flowers - pH 5.5 or lower
Pink flowers - pH 6.5 or Higher
Purple or a mix of blue and pink flowers on the same plant - pH 5.5 and pH 6.5

***Note: Only the flowers of bigleaf (Hydrangea macrophylla), also known as mopheads and lacecaps, can change color. Other types such as oakleaf hydrangeas or hydrangeas 'Annabelle' only bloom in white or cream.

Enjoy!

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