Magnesium and Hydrangeas

Changing your Hydrangea to Red

Not all hydrangeas have the ability to turn red, but many can. White or cream hydrangeas, for example, will remain the same color no matter what you do, but the other natural colors can be converted to the light or dark pink color. This is because the color of the blooms is determined in part by the pH and aluminum levels of the plants, and these things can be altered using chemicals that contain magnesium.

Magnesium is used to interact with the plant and influence the natural processes of growing and blooming. A chemical with magnesium in it will help to inhibit the aluminum in the soil or the plant. Aluminum is what produces a bluish color in the plant and stops the plant from showing the reddish color that you desire.

You must add the right amount of magnesium to your soil to produce a reddish color, and this is often determined scientifically. Deep pinks are achieved through a soil pH level of between 6.0 and 6.5, and this will lower the acid level in both the plant and the soil that it lives in. Adding magnesium will lower the pH level of the soil to this range if done correctly. Different chemicals with magnesium are used in various fertilizers, and these can be purchased at many gardening and flowering stores. These also increase the alkalinity of the soil, and this helps to promote the pink and red colors.

When you are using magnesium on your hydrangea plants, you are likely doing this to deliberately change their color to a pink or red. This can be done over the length of an entire season. Because magnesium works at about the same rate as the other chemical compounds, it may take several months to get the color you desire. You might have to wait for the next season's blooms. Follow the manufacturer's instructions for your magnesium additive so you don't damage the hydrangea or inhibit its growth by adding too many chemicals to the soil.