Hydrangea color can be changed by adjusting the pH of your soil, but is not an instant change, and not all hydrangeas can be altered.
If you have a big-leaf or mountain hydrangea you can change the color with time but only if it is already blue, purple or pink. If the flowers are white they can not be changed. It may also be difficult if the flowers are an extreme hue to begin with.
It is much easier to change from pink to blue, but blue to pink is not impossible! In order to begin the color-change process, you will need to test your soil. You may not have to change the soil… if you bought a pink hydrangea last year and decided that your judgment was off, your soil may automatically change your hydrangea over on its own after a few years without you having to lift a finger. But you’ll never know until you test!
Blue hydrangeas love acidic soil with a pH between 5.2 and 5.5
Pink hydrangeas thrive in alkaline soil with a pH between 6.5 and 7.0
If you want to acidify your soil for a deep blue hydrangea you will need to apply Color Me Blue in 60-day intervals over the course of the growing season.
Same goes for pink! Apply Color Me Pink or Garden Lime in 60-day intervals over the course of the growing season. Also, take note if your hydrangea is planted near a sidewalk or walkway. Lime that leaches from concrete will make it more likely that your hydrangea will be or will turn pink. Your color change will be gradual and may take a few years! Don’t get discouraged, you will start to see your blooms change eventually. Your hydrangea may possibly bloom with three different colors on it at one time! How awesome would that be?