When Should You Prune Hydrangeas?
Do you need to prune your hydrangeas, but aren't sure if it's better to prune them in the spring or the wintertime? Picking the perfect time to prune them can be the difference between full or failed blooms come summertime. In this article, gardening expert and hydrangea enthusiast Jill Drago examines the best time of year to prune your hydrangeas.
Hydrangea pruning gets a bad reputation as being complicated. However, there are some simple steps you can follow to properly prune your hydrangeas. There is one element that makes things tricky, though, and that is timing. A very common question regarding pruning hydrangeas is whether to do it in the spring or winter.
Truly, it boils down to what type of hydrangea you have in your garden. There are many different species of hydrangea, and each has different care needs. Just don’t get too confused with the several hydrangea care myths out there! There is no single window that is best for pruning all hydrangea types.
Once you have determined what species of hydrangea you are working with, it will be very easy for you to make a decision about what season you should do your pruning, spring or winter. Here we cover the most popular hydrangea types and the best season to prune them!
The Short Answer
Whether you should prune hydrangeas in spring or winter fully depends on the type of hydrangea you have. Hydrangeas can be old wood, new wood, or reblooming varieties. Smooth and panicle hydrangeas bloom on new wood and should usually be pruned in the late winter to early spring.
Bigleaf, mountain, oakleaf, and climbing hydrangeas bloom on old wood and should typically be pruned after flowering has occurred. Reblooming hydrangeas should be only pruned in late spring when needed. However, there are many other factors to consider when deciding whether to prune your hydrangeas in the spring or winter, no matter what type you have.
The Long Answer
Simply put, pruning means cutting away dead, damaged, overgrown, or unwanted stems from a plant. Gardeners prune their plants to keep a good shape or size, to promote flower production, and to maintain the health of the plant.
It is not always required to prune hydrangeas every year. Oftentimes your hydrangeas will have intense blooms without any trimming. However, many hydrangeas can benefit from a good pruning every couple of years.
To have healthy, bountiful, and shapely hydrangeas, it will be very helpful to determine what type of hydrangea you have. If you already know your species, then you are ahead of the game. Otherwise, you will need to do a little bit of monitoring to determine what type of hydrangea you are working with.
If you notice a lot of new growth in the springtime and also notice that the flowers are only forming on those stems, you have a new wood blooming hydrangea.
If you get out in the garden in the winter and take a look at your hydrangeas this is a helpful time to learn about them. There are no buds present on new wood bloomers over the winter, so if you notice some buds you likely have an old wood bloomer.
Identifying Hydrangea Types
There are six types of hydrangea and they can be divided into two groups: those that bloom on new wood and then those that bloom on old wood.
To make things just a little bit more complicated, some of these old wood bloomers are also reblooming varieties. This means they bloom on new AND old wood. Knowing the difference between these types is the first step in determining whether to prune your hydrangeas in the spring or winter.
Hydrangea arborescens and Hydrangea paniculata are species of hydrangea that are considered “new wood” bloomers. This means the flower buds form on the new growth that emerges in the spring. These are ideal for colder climates in USDA hardiness zones 2-5.
Other common names for this species of hydrangea are smooth hydrangeas or Annabelle hydrangeas. They typically have white or pink flowers that bloom in a round mophead or sometimes lacecap-style shape. Buds form in early spring on new wood and bloom in early summer.
Commonly called panicle hydrangeas, these large shrubs are identified easily by their cone-shaped flower clusters. These flowers bloom in white or light green then turn pink or red in the cooler months. Their buds form in late spring or early summer on new wood. They are usually the last to bloom starting in midsummer to later in the summer.
All of the remaining species of hydrangea bloom on “old wood” which means the flower buds form on growth from the previous growing season in the late summer or early autumn.
Because these hydrangea buds need to survive a cold winter freeze, these species do better in warmer climate zones. These remaining species are Hydrangea anomala, Hydrangea macrophylla, Hydrangea serrata, and Hydrangea quercifolia.
Better known as climbing hydrangea, Hydrangea anomala can reach lengths of up to 40 feet when supported. The white flowers grow in flat, sometimes lacecap, clusters and bloom from late spring and into early/midsummer.
Colorful bigleaf hydrangeas are best known for their bright pink, red, purple, or blue blossoms that appear in midsummer, but they can also bloom in white. The flowers can grow in large, showy spheres or in delicate lacecap form. They are popular in landscapes and in floral bouquets.
Light pink or blue lacecap-style flowers cover the surface of Hydrangea serrata, or better known as mountain hydrangeas, from early summer to the middle of the season. These shrubs tend to be smaller in size, about 2-4 feet tall and wide.
These hydrangeas are recognizable by their large, oakleaf-shaped leaves. This is why they are commonly known as oakleaf hydrangeas. Their large, white, cone-shaped flowers bloom early in the summer and are often the first to appear. These flowers turn pink or red in the cooler months before fading to a light brown color, which adds seasonal interest.
Reblooming hydrangeas are variations of two species, Hydrangea macrophylla and Hydrangea serrata. They faithfully bloom from early summer through the fall. Ideally, they grow in mild climates of USDA hardiness zones 5-7, but can survive in warmer and cooler climates as well, ranging from zones 4-9.
There are several bigleaf hydrangeas that bloom on old wood as well as new wood later in the season. Some examples of these are Endless Summer®, Let’s Dance®, and Seaside Serenade®.
Reblooming mountain hydrangeas bloom primarily on old wood in the early to midsummer months. The second bloom comes later in the season. Some examples of reblooming mountain hydrangeas include Tuff Stuff™ and Forever & Ever®.
When to Prune New Wood Hydrangeas
New wood hydrangea species will do well if they are pruned in the late winter OR the early spring. This is because the flower buds form on the growth the plant produces in the spring, so the risk of removing the buds is limited. It is best to prune away dead or weak branches only and not attempt to shape the shrub too much.
A benefit to pruning hydrangeas in the early spring is you will be able to clear up all of the winter damage. As long as you prune before those buds are set, you will be safe.
You also get to enjoy the dried flower look all winter when you wait until spring to prune. Just be sure to properly prepare your hydrangeas for the winter cold so they can last through the season.
You can also wait until early winter to prune your hydrangeas. The instructions are the same for winter as they are for spring.
It is also possible for you to complete this task in the fall. The only problem with pruning a little early is you will lose some of the fall beauty, and you may deprive your hydrangea of the ability to store some more food to get it through the winter.
Because your hydrangeas will still be vibrant in the fall, you will have a very good idea of the size and shape of your plant. This makes it a great time to neaten up some wonky branches, or at least make plans for whether or not you need to do any winter pruning.
When to Prune Old Wood Hydrangeas
Old wood blooming hydrangeas don’t require a lot of pruning. If you are going to do so, prune flowering stems back just after they finish blooming in order to maintain your flower power for next year. These hydrangeas set their flower buds in the fall when the older flowers have passed. Waiting too late in the summer season means you prune off next season’s flowers.
For best results, do not deadhead or remove spent blooms on mophead varieties until early spring. You may deadhead lacecap varieties. This not only adds seasonal interest but also helps protect the plant from the cold.
When you are ready to start pruning, take it one stem at a time. Cut one or two of the older stems down to the soil to encourage a fuller shrub. For size, find the second pair of leaves under the flowerhead and cut there.
If your hydrangea has become too neglected, old, or damaged, do a hard prune. This means cutting the whole plant down to the soil level. The best time to do this is in late winter or early spring. Flowers will not bloom in the upcoming season, but your hydrangeas will be rejuvenated for many years.
When to Prune Reblooming Hydrangeas
Hydrangea macrophylla has been hybridized and is available as a reblooming hydrangea, such as Endless Summer®. Reblooming hydrangeas will bloom on old wood as well as new wood.
It can be tough to figure out when to prune these hydrangeas without forfeiting some blooms. Typically these hydrangeas will only require deadheading and won’t frequently need to be pruned for size, only for maintenance.
If you have planted Endless Summer® hydrangeas or other reblooming types, spring is a good time to look through these hydrangeas and remove any dead wood that is noticeable. At this point, many of the stems should have some buds visible on them. If you come across a stem that has no buds, this is likely deadwood and can be cut right to the ground.
If you are unsure if your hydrangea will rebloom, it is best to save your pruning until the fall.
Typically hydrangeas are cut back to keep a good size or shape and to promote flower production. However, there are times when hydrangeas of any type will need maintenance or selective pruning.
This type of pruning is when there are branches that are dried out, dying, not producing any leaves or flowers, or have signs of disease or pest damage. Branches that are growing too close to others or not flowing with the rest of the plant may also need to be cut back. The best time to do such maintenance is in the late winter or early spring.
Remove any old growth. You should be able to spot these stems as they will have some peeling bark, and will be very easy to remove by hand.
This step will help rejuvenate your plant and increase airflow throughout the shrub which will help keep diseases at bay. A healthy hydrangea should have upright, straight, and spaced-out branches.
Different from pruning, deadheading is the removal of spent flowers from the rest of the plant. Flowers that are dying, dried out, brown, or drooping can be cut back at any time in the spring or summer.
However, it is best to wait until you are not in the middle of a summer heatwave. Cutting away these spent flowers helps the plant focus its energy on generating more blooms.
Be sure not to clip off too many flowers growing on old wood if it is late in the growing season. By mid-fall, any spent blooms can be left on the plant for seasonal interest. Until you are ready to do major clipping, the fall is a great time to deadhead those fading flowers from old wood hydrangeas. You can save them and use them in dried arrangements or compost them.
Don’t forget that leaving the dried hydrangea flowers on your plants makes really nice winter interest for your gardens. The remaining flowers also can protect any of the newly forming growth from winter damage or a late spring frost. You can save your deadheading for the spring when you do your previously planned pruning.
To deadhead your hydrangeas correctly for better blooms, simply snip below the spent blossoms and close to a set of leaves. This will help to keep your hydrangea attractive and healthy.
Pruning Mistakes to Avoid
Knowing the species is helpful in determining whether spring or winter is best for pruning hydrangeas. But, timing is everything when it comes to keeping these beautiful shrubs looking their best.
There are some mistakes to avoid when pruning hydrangeas, such as pruning too often in the season, completely neglecting them, and pruning at the wrong time during the hot summer months.
Pruning Throughout the Season
There are some gardeners who feel they need to prune their hydrangeas throughout the season to keep them from getting too large. This poses a big risk, as the flower buds can be removed without you knowing.
Pruning throughout the season is also ineffective in keeping the shrub at a shorter height. This is because pruning stimulates new growth and this will cause the shrub to grow back to the original height, or even bigger in some instances!
Though it is not always necessary to prune hydrangeas, neglecting them can cause some problems. Your hydrangeas can become overgrown and not get enough airflow when neglected. This can hinder the proper growth of the plant.
Hydrangeas can also stop blooming entirely when neglected, holding back on the beautiful blooms they are so well-known for. When a hydrangea plant is wasting energy on producing leaves and instead providing support for dying or older branches, it can cause the plant to halt production on blooms.
Cutting away inadequate branches can keep your hydrangea healthy and at a good size and shape. Ultimately the plant will produce large, bountiful flowers when maintained and pruned when necessary.
Pruning at the Wrong Time
One of the biggest reasons hydrangeas don’t bloom is because they have been pruned at the wrong time and the flower buds have been cut right off. This is a common occurrence, and luckily it will only affect the flowering of your hydrangea shrub for one season.
Summertime is the prime time for hydrangeas. Your healthy hydrangeas should be full of beautiful flowers. In general, pruning in the prime of summer is not recommended.
Typically the summer months are hotter and drier than the rest of the year. Pruning in these conditions can overstress your hydrangeas which can lead to issues such as insect or disease infestation. Only prune new wood varieties in late summer once the flowers have bloomed.
When to Prune Hydrangeas at a Glance
Don’t let yourself become intimidated when it comes to pruning your hydrangeas. It is an easy process that will be well worth your time and energy. Knowing the best time to prune hydrangeas, whether in the spring or winter, will greatly benefit the health and vitality of your plant. Take a deep breath, and happy snipping!