How to Make Your Hydrangeas Change Color
Love your hydrangeas but want to see how they would look in a different color? Depending on the variety, you can change their color yourself. Here’s what you need to know.
Not all hydrangeas can change color
Before going any further, it should be noted that not all hydrangeas are capable of changing color. Hydrangeas with this ability include some large-leaved hydrangeas ( H. macrophylla ), especially Mophead and Lacecap species, and H. serrata cultivars. And if pink and blue hydrangeas of these varieties can change color, then with white flowers – no.
How do hydrangeas change color?
The Farmer’s Almanac recommends waiting until a hydrangea plant is at least two years old before attempting to change the color of its flowers. It’s also important to keep in mind that the color change doesn’t happen instantly: it usually takes weeks or months to transform.
Hydrangea color is determined by how much aluminum the plant is able to absorb from the soil , and this depends on the pH of the soil.
Soil with a lower pH makes it easier for plants to absorb aluminum, which usually makes its flowers blue. Meanwhile, higher pH soil makes it harder for the plant to access aluminum, which usually means its flowers will be pink.
How to change the color of a hydrangea
First, you need to check your soil’s pH . Also, make sure you have some aluminum sulfate. Here’s what to do next:
How to turn pink flowers blue
To go from pink to blue , increase the acidity of the soil. You can do this by applying a 1/4 ounce aluminum sulfate solution per gallon of water three times a year, starting in the spring.
Repeat the procedure after three to four weeks, and then again after three to four weeks. When you use an aluminum sulfate solution in the spring, also apply a 25-5-30 fertilizer according to the manufacturer’s instructions.
How to turn blue flowers into pink?
To go from blue to pink , increase the alkalinity of the soil. You can do this by spreading ground limestone (dolomitic lime) at a ratio of four pounds per 100 square feet in the spring or fall and making sure it gets plenty of water. At the same time, apply 25-10-10 fertilizer to the plant, following the manufacturer’s instructions.
And if you have water that is high in minerals (also known as hard water), it can help turn blue flowers pink.