The Secret to Reblooming Hydrangeas: Top Tips for All-Summer Color

Hydrangeas are among the most popular flowering shrubs, thanks to their large flower clusters and ability to thrive in both sun and shade. The only downside is that most of these shrubs only flower for a month or two.

That’s where reblooming hydrangeas come in. These varieties produce flowers multiple times per year, creating an almost continuous display of color during the summer.

Choosing the correct type of hydrangea is key to long-lasting color, but there are also a few tips that can help the plants produce lots of healthy blooms. I’ll cover how to select the right hydrangea variety and provide care that leads to a profusion of flowers this summer.

Choose the Correct Variety

If you want to enjoy billowy blooms from spring through fall, choosing the correct variety is the first step. There are dozens of different hydrangea species and hundreds of varieties within these species. Many people can differentiate hydrangeas based on their varied flower shapes and colors, but these plants also bloom at different times.

One of the major factors that impacts bloom time is whether the plant produces flowers on new or old wood. Varieties that bloom on old wood form their flower buds in the fall and bloom the following spring and early summer. Those that bloom on new wood form buds in the spring and flower in the summer or early fall.

Reblooming hydrangea varieties produce buds and flowers on both new and old wood. The old wood flowers appear first, followed by the new wood blooms. When you combine these two blooms, these shrubs are covered with flowers from late spring through early fall.

The Endless Summer® hydrangea is the original repeat bloomer and remains one of the most popular varieties for long-lasting color. You can also find newer cultivars that produce lacecap and conical blooms. ‘PeeGee,’ ‘Candy Apple™,’ and ‘Pop Star®’ are a few other types of reblooming hydrangeas.

Recognize the Impact of Temperature

As I mentioned above, the key to reblooming hydrangeas’ long-lasting flowers is their ability to flower on both new and old wood. But this double bloom isn’t guaranteed.

Flowers that appear early in the season are the result of buds that appeared on old growth the previous fall. These buds remain on the plant throughout the winter, so they’re susceptible to cold damage. If you live in zone five or below, these old-growth buds may die during the winter. You’ll still enjoy flowers on new growth, but the shrub’s bloom time will be condensed.

When you’re looking at reblooming hydrangeas, pay close attention to the plant’s hardiness zone. Some varieties are cold-hardy down to zone five, but others can survive winters in areas as cold as zone three. 

Avoid Extensive Pruning

Many gardeners make pruning hydrangeas a yearly garden ritual. Hydrangea varieties that bloom solely on old growth or new growth are easy to prune since they only produce flowers on one type of growth.

You can prune varieties that bloom on old wood in the late summer after the plants have flowered, but before they produce buds. This prevents you from pruning small flower buds that will soon turn into impressive blooms. The late fall or early spring is the best time to prune varieties that flower on new wood.

The trouble with reblooming hydrangeas is that pruning almost always means removing flower buds! If you prune in the late fall, you remove buds that appear on old growth. Pruning in late summer means you’ll remove flowers that emerged from new growth.

Fortunately, reblooming hydrangeas will remain healthy without extensive pruning. You shouldn’t hesitate to remove dead or dying wood, but avoid using your shears to trim off excessive foliage.

Provide the Ideal Light Conditions

Just like hydrangeas vary in flower shape and color, they also have unique light preferences. Some varieties thrive in full sun or a few hours of afternoon shade, and others prefer dappled light throughout the day.

Before you plant a new hydrangea, look at the location throughout the day. Does it receive morning shade and afternoon sun? Full sun? Just a few hours of light in the late afternoon?

You can use these light conditions to find a hydrangea variety that will naturally thrive in this environment. This practice is easier than choosing a shrub and then finding the right location for it.

Provide the Proper Nutrients

Hydrangeas require a host of nutrients to remain healthy and produce blooms. Supplying your shrub with these nutrients will ensure the plant has all it needs to conduct the energy-intensive process of producing buds and flowers.

Most hydrangeas benefit from a balanced fertilizer throughout the growing season. You can add a slow-release fertilizer once in the spring, or apply fertilizer multiple times throughout the growing season. Avoid fertilizers that are high in nitrogen and low in phosphorus and potassium, since this can encourage lots of vegetative growth but few blooms.

Soil pH also plays a significant role in determining whether nutrients in the soil are available to plants. Hydrangeas thrive in soil with a pH between 5.0 and 7.0, although the pH level can affect the bloom color of certain varieties. This color change occurs because the availability of aluminum changes with soil pH.

If your soil pH is above 7.0, you can lower it by applying elemental sulfur to the soil. The sulfur will take at least a few months to alter the pH, so don’t expect immediate results.

Water Well, Especially in Summer

Hydrangeas benefit from consistent and moderate moisture, especially during dry, hot summers. If you go more than a few days without rain in the summer, provide your shrubs with a long, deep drink. Watering slowly and deeply near the base of the plant allows the water to percolate into the soil, reaching the plant’s deepest roots.

Mulching around the plant can help conserve moisture throughout the year. Add a few inches of wood chips, straw, or another organic material to trap in moisture and limit weed growth.

Deadhead Old Flowers

Although deadheading old blooms isn’t necessary, it can help encourage the plants to produce new flowers. Remember that reblooming hydrangeas produce flowers on both old and new growth, so removing dead flowers won’t cause the plants to reflower on the same stem.