Hydrangea Flower Losing Color. You can change the color of some varieties of hydrangea by adding aluminum sulfate to make the flowers more blue or by adding dolomite to make them pink. Excess moisture will leak through the drainage holes.
The leaf plate turns yellow with bright green veins. If the soil has either a high pH or is low on aluminum the hydrangea flower color will be pink. The disease appears as follows.
Most of the time the color depends on the pH.
The more alkaline the soil the pinker the flowers. However there may also be problems. Finally soil acidity may be responsible for altering or fading flower color. 22062020 Aluminum gives you blue flowers.