How to Prune Hydrangeas in 7 Simple Steps

How to prune hydrangeas is one of the most common questions I get from friends and family about their plants. It’s right up there with “why aren’t my hydrangeas blooming” and “how do I turn my hydrangeas blue”. While those two questions might be easier to answer, properly pruning your hydrangea can be more of an art.

Hydrangeas are easy to grow, and a fairly low maintenance plant… until it comes to pruning. Pruning at the wrong time can cost you your blooms for next season. It could cause more blooms that are much smaller than anticipated.

I admit, proper hydrangea pruning can be a little intimidating! But, once you read through these steps you will feel much more confident. Let’s take a look at each step you’ll need to take in order to properly prune your hydrangeas.

Step 1: Identify Species

Figuring out what type of hydrangea you have is the most important step of pruning. This is because some species bloom on what is called “old wood” which is growth from the previous season. These species are: macrophylla, serrata, quercifolia, and anomala.

“New wood” blooms can be found on the growth from the current season. These species are arborescens and paniculata. These species are known to take a bit more sun, and can be pruned later in the fall.

The old wood species don’t typically require a lot of pruning. They are at their best when they are left to grow freely, and pruned only for containment and to remove winter-kill. Use the following table depending on your species, and to determine the best time to start pruning.

Hydrangea Species	When to Prune Hydrangeas
Quercifolia	Quercifolia can be left alone until April before they are pruned.
Anomala	For anomala, it’s best to prune after flowering in late June, simply by removing spent blooms.
Macrophylla & Serrata	Both Macrophylla and Serrata have big heads of mophead, and lace flowers, respectively. They respond to pruning after flowering in late June.
Arborescens & Paniculata	With new wood varieties, it’s best to prune in the late fall.

Don’t Know Your Species?

If you are unsure what type of hydrangea you have, there are a few steps you can take to identify. Hold off on pruning until the next season, and pay close attention this season. Watch for the amount of growth that comes from the ground.

If you notice many new stems, and also notice that the flowers on this hydrangea are ONLY on those new stems, then you have a new wood bloomer. If you don’t notice much new growth coming from the soil line you most likely have an old wood bloomer.

If you are working with a new wood bloomer, you really can’t go wrong, it is best to prune in the late fall.

Flower buds are not present on new wood blooming plants over the winter. It may be worth a trip through your garden during the winter to see if your hydrangea has any formed flower buds. If it does, this means that your plant will be blooming on old wood.

If you don’t want to wait, you can opt for following the pruning tips for old wood bloomers. This will keep your flowers safe. If, at the end of the season you notice many woody stems with no new growth, you’ve got yourself a new wood bloomer.

Step 2: Gather Tools

Before you get started, make sure you have everything you need to get the job done. The best type of tool to use to prune hydrangeas are bypass shears. Bypass shears cut like scissors, but the blades pass by each other to make a cut.

Give your shears a quick wipe down before you get started to remove any debris. It is recommended to clean your pruning shears with rubbing alcohol or diluted bleach and allow it to dry before you start pruning. This step will help to eliminate any lingering insects and their eggs, as well as any diseases you may have encountered.

 It is a good idea to have a bucket to collect your debris. This will make cleaning up quicker in the long run and avoid any of the pruned plant material to collect around the base of a plant. Build up of plant material around the base of a plant can lead to diseases.

I would also suggest a good pair of garden gloves, and some safety glasses. The amount of times I have gotten poked in the eye by a rogue hydrangea branch that I somehow didn’t see is just embarrassing. But it does hurt, and it can be easily prevented.

Sunglasses also do the trick here. The same goes for your arms, if you are working on many hydrangeas and are reaching down into the base of the plant for cleaning or pruning you may end up with some uncomfortable scratches up and down your arms and on your hands. Be sure to wear long sleeves or long garden gloves to help prevent any scratches on your skin.

Step 3: Remove Old Flowers

In order to have the best view of your plant it is a good idea to remove any of the spent flowers. Simply snip off the old flower just below the base of the flower.

Step 4: Locate New Buds

Before making any cuts locate any new buds that may be formed on your hydrangea plant. These buds could be leaf or flower buds, but either way its best not to cut any of the formed buds off.

Step 5: Remove the Oldest Growth

Locate one or two of the older branches on your plant. These can sometimes be identified by peeling bark. Sometimes you can just wiggle them right out of the crown of the plant. Cut no more than one third of these branches right down to the soil line. This will help to revitalize your plant, and help to increase the size of your flowers, and the overall health of your hydrangea.

Step 6: Get Cutting!

Once you’ve located the stems that are safe to cut, move down the stem with your fingers until you reach a set of leaves, and make a nice clean cut just above this set of leaves.

I tend to start at the top and center of a shrub when pruning, which gives me a good guide of how much to cut from the rest of the plant and helps me from cutting too much. 

I like to make small cuts at first. Once I have done my initial prune, I take a step back and take a look at how the plant is shaping up. Then I can return to pruning for shape.

Step 7: Damage Control

Once you’ve pruned the growth that you were wanting to remove, check the plant out and remove any dead branches, or branches that may have broken throughout the season. Eliminating these branches will help airflow throughout the plant.

New Wood Pruning Tips

New wood bloomers give you a bit more flexibility when it comes to the type of pruning and the timing of pruning. These hydrangeas will be tolerant of your pruning no matter when you do it. However, it is recommended that you prune in the late fall or springtime.

If you miss these time windows, just be sure that you don’t see any new flower buds that have been set before you begin making your cuts.

Follow the above steps for prepping your pruning adventure. Next, you will need to decide if you want to prune for the shape and health of the plant, or if you want to prune to increase vigor and also the size of your flowers.

Pruning for Shape

To give your new wood blooming hydrangeas a healthy cut, a good rule of thumb is only to remove one third of growth. This means in height, and also from within the plant. This will allow enough of the plant to remain and will still promote new healthy growth and happy blooms

For me, this is the way to go. I like to have the built in stability of the woody growth. I also like to know where my plants are in the winter time. You can always go back in and remove a woody stem here and there if you notice that one section of your plant tends to be more woody than the rest.

Before cutting, take a good look at the plant and decide how far back you want to cut it. It may be the full one third of the height, or it may be a little less. Once you’ve found that spot, locate a set of leaves that are close to that spot, and snip just above those leaves. Only leave a small amount of stem above those leaves. Continue on with the rest of the plant.

Once you have finished, take a step back and admire your hard work. This is also a good time to take a good look at the new shape of your plant. You won’t want your stems to be all the exact same height, but they should be close.

Pruning for Flowers

New wood bloomers produce their new branch growth as well as their flowers in one season. Do not be hesitant to be a bit aggressive with your pruning. If you are longing for larger blooms, try cutting your hydrangea back to the ground in the very early spring. Make sure you do not have an old wood bloomer!

Simply use your pruning shears and cut each individual branch right to the soil line. This type of cutting will help to increase your flower size. Take this opportunity to also clear out the leaves that have collected in your hydrangea over the fall and winter seasons. However, if you prefer sturdier stems avoid this type of hard pruning and prune normally.

Support

Many species of new wood bloomers carry very large flowers. Despite the recent hybridizing to prevent dropping blossoms, it can still sometimes happen after heavy rain. One easy way to prevent this is by leaving some of the older stems as a sort of framework. Give them a good cut to knee-high height. These stems will aid in the support of the new growth and help to keep those big blossoms upright.

Reblooming Hydrangeas

A reblooming hydrangea blooms on both old wood and new wood. Tricky huh? The good news with these hydrangeas is they don’t often require pruning for size. They typically only require deadheading to remove spent blooms.

In the springtime, the leaves should have emerged, and the flower buds should be visible. This is a good time to look through the plant and remove any dead wood by cutting it to the soil line. Dead wood will not have any leaf or flower buds on it.

It may also wiggle very easily out of the plant. Another test you can try is using your finger nail to scratch the surface of the branch, if there is green underneath your scratch you may want to leave it alone for a little longer. The show of green could mean there is still life within that branch.

Winter Interest

When it comes to pruning or deadheading your hydrangeas, keep in mind that it is not mandatory to prune every year. Many hydrangeas don’t actually require pruning to promote blooming. Dried hydrangeas left on your plants can make really nice winter interest in your gardens.

Flowers that are left on your plant to dry will take on an aged color, and may just end up blowing right off your plant and through your yard like a tumbleweed. Leaving your flowers uncut can also help to protect new growth from winter damage from frost or wind.

Total Plant Rejuvenation

It is possible for hydrangeas to become overgrown if they have not been cared for. If you have inherited a plant like this, or are looking to give an older shrub a little love the best thing you can do is cut the stems of the plant back to the ground. This will help to breathe new life into your plant. This severe type of pruning will likely cause your blooms to be delayed for a season or two