How to magically change the color of your hydrangea!

Did you know that some flowers change their color?

Believe it or not, hydrangeas are flowers that can change color depending on the type of flower you are growing and the pH of the soil. You can influence what colors are expressed by focusing on the quality and pH of your soil.

If you are new to gardening and want to learn how to change the color of hydrangeas, you can learn more by following the tips and tricks described below. For more tips on how to maintain your hydrangea, see our article here.

Do all hydrangeas change color?

Unfortunately, not all hydrangeas can change their color at will. Only the flowers of certain types of hydrangeas, such as the Bigleaf Hydrangeas (H. macrobilla), Landscape, and Mobhead Hydrangeas, can change their color.

However, the basics are simple. The relationship between pH and color is complex and more closely related to pH value. The presence of aluminum ions in the soil - as well as the extent to which a particular type of hydrangea absorbs them - plays a role in color expression.

The color change does not happen immediately but takes weeks or months - sorry, there is no magical color change here! It should also be noted that it is much easier to turn blue flowers pink than it is to turn pink flowers blue. Some cultivars change colors much more easily than others.

What affects the color of hydrangea?

If you want to grow blue hydrangeas, do so in acidic soils. Pink and red hydrangeas thrive in neutral or alkaline soils.

As a quick guide, hydrangeas that grow blue flowers will grow in acidic soils with a pH of less than 5.5. Plants that grow in soils with a pH above 5.5 will produce pink flowers.

Unfortunately, white hydrangeas are generally not affected by soil pH. Whatever you do the white flowers will be white and prefer the same conditions as the pink and red hydrangeas.

How to change the color of your hydrangea

Wait two years

Do not try to change the color of your hydrangeas until they have been on the ground for at least two years. If you try to change the colors faster than that, you will find that they do not return well because they have not been given enough time to recover from the shock of planting.

Then, when you are ready to plant, test your soil. Check with a local nursery to find out how much aluminum sulfate to use to change the acidity of your soil, and then follow the guidelines for changing the color, which we describe below.

You can test your soil by collecting a small sample of soil from your garden, as close to your hydrangeas as possible. Pour a little distilled white vinegar into the soil in a container. If it is fissile, the pH level will be higher - your soil is alkaline. Otherwise, it is acidic or neutral.

Replacing pink hydrangeas with blue

Want to make your pink hydrangea blue? You need to increase the acidity of your soil. To do this, apply a solution of a quarter ounce of aluminum sulfate three times a year to one gallon of water. This colorless salt can be purchased at any garden center.

Apply the first application of aluminum sulphate to the soil as soon as the plants start to grow in the spring. Do this twice during the growing season, at intervals of three to four weeks. Once a year, in the spring, apply a balanced fertilizer.

Changing the color of blue hydrangeas pink

If you want to make the change the other way around, you need to increase the alkalinity of the soil (or reduce its acidity). To do this, you need to add ground lime or dolomitic lime to the soil in the spring or fall. Do this at the rate of 4 pounds per 100 square feet. Water well.

It is important to test your soil before adding this solution - excessive alkalinity can cause the leaves of your plants to be affected by chlorosis or die.

You can apply 25-10-10 fertilizers in spring or fall. A compost that is slightly high in phosphorus should do the trick, and it will also help prevent aluminum from creating toxic symptoms in your hydrangeas.

Using natural soil corrections

When you try to change the alkalinity or acidity of your soil, remember that you do not have to rely solely on ground lime or aluminum sulphate to do this make.

There are other natural remedies that you can use. If you need to acidify the soil, do so by increasing the presence of aluminum with corrections such as compost, coffee grounds, or pine needles.

Other things to keep in mind

Your hydrangea flowers will change color automatically in the fall, but not necessarily the way you want them. They sometimes turn pink, green or brown, and they die each fall.

The hardness of your water can also affect the color of the flower. Hard water (high mineral content) will turn your blue flowers pink. If you want to avoid this, use rainwater to water your hydrangeas.

When you water your hydrangeas, do not forget that the acidity or alkalinity of the water can also affect the color of the flowers.

When you first bring your nursery hydrangea home, it may be a color - but don’t be surprised if its color changes when you plant it outdoors! Remember, how you change the color of your hydrangeas will eventually depend on your soil type and pH - so you will be pleasantly surprised when you get your new chameleon plant in the ground.