How to Improve the Color of Your Hydrangeas

No matter how big your hydrangeas grow, a stunning display is about quality as much as quantity—which means faded and washed out blooms have no place in your garden. If your hydrangeas are getting too much sun, too little water, or the wrong type of nutrients, those pretty petals can turn pale.

But with regular watering, a partly shaded spot, and careful attention to the acidity of your soil, you can boost your hydrangea blooms to bold blue or pretty pink for a season-long show of gorgeous hues. (With some types of hydrangeas, you can even change the color by changing the pH of the soil.) We asked two pros—gardening expert Melinda Myers and Amy Enfield, a horticulturist at ScottsMiracle-Gro and Bonnie Plants—for their best advice on improving the color of your hydrangeas.

Don't Plant Hydrangeas in Direct Sunlight.

While the colors of a hydrangea's flowers will naturally fade over time, Enfield says that planting the shrub in direct sunlight is a surefire way to speed up that process. "Too much direct sunlight, especially in the afternoon, will cause the flower color to fade quicker than normal," she says. "Your hydrangea should be planted in a spot that is protected from the hot afternoon sun, but still receives the cool morning sun."

Water Hydrangeas Regularly

Along with too much direct sunlight, too much—or too little—water can cause hydrangea flowers to fade at a faster rate. "Hydrangeas should be watered thoroughly and deeply whenever the top inch of soil is dry," Enfield says. "Be careful not to overwater the plant, which can restrict air flow around the roots."

Fertilize Hydrangeas Carefully

According to Meyers, more isn't always better when it comes to fertilizing plants; hydrangeas are especially apt to fade or flourish based on the soil where they're planted, and bigleaf hydrangeas can even have their color changed from blue to pink based on the acidity of the soil. "Too much nitrogen in the soil can result in hydrangeas with less colorful blooms," she says. "A soil test will tell you how much (and what kind) of fertilizer is needed to ensure your blooms grow as big and bright as they deserve to be."

Boost Blue Hydrangeas With Aluminum

Soil with a lower pH—and a higher acid content—provides bluer blooms; if your soil test shows a pH above five, add aluminum sulfate or another acid to lower the pH and create a brighter, bolder blue. "The acidity of aluminum is what influences the blue color of flowers," Myers says. "In alkaline soil, where there isn't as much aluminum available to the plant, try adding aluminum sulfate—or an equally acidic element like ammonium sulfate—to the soil to brighten the blues of your blooms."

Pink Hydrangeas Need a Higher pH

Pink-and-red hydrangeas, however, perk up their color in a soil with a higher pH—one that's less acidic and more alkaline—of about six. To lower the aluminum or acid content in your soil, spread wood ashes or limestone over the ground and use a hoe or tiller to work it into the soil. "Or plant panicle or oakleaf hydrangeas with flowers that start white and fade to pink and red later in the season," Myers says.