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Cutting down hydrangeas


Pruning Hydrangeas - FineGardening

I know people are confused about how to prune hydrangeas because I get asked about it all the time. The three most common reasons for their confusion are the plant’s dead-looking appearance in winter, its failure to bloom in summer, and the reasoning that because it’s a shrub it needs to be pruned. But these popular woody plants can live long, floriferous lives without ever feeling the cold blade of a pair of Felcos. Hydrangeas, though, can handle pruning (which, if done at the wrong time, may be the cause for the lack of flowers), and sometimes you might want or need to cut them back a bit. For example, you may not like the look of the fading blooms, or your shrub may be a bit too tall. Pruning hydrangeas can also improve a shrub’s vigor and increase the size of its flowers.

Not all of these shrubs should be pruned at the same time. Those that bloom on old growth should only be pruned after flowering. Others bloom on new growth and should be pruned before they wake up in spring or as they are going dormant in fall.

Hydrangeas that bloom on old wood

Bigleaf hydrangea. Photo: Steve Aitken

Bigleaf hydrangea. Photo: courtesy of hydrangeasplus.com

Oakleaf hydrangea. Photo: Melissa Lucas
  1. Bigleaf hydrangeas (Hydrangea macrophylla cvs., USDA Hardiness Zones 6–9)
  2. Bigleaf hydrangeas (H. serrata cvs., Zones 6–9)
  3. Oakleaf hydrangeas (H. quercifolia cvs., Zones 5–9)

Prune after the flowers start to fade in late summer

To determine if your hydrangea blooms on old wood, think about when it flowers. Shrubs with this characteristic generally begin blooming in early summer and peter out by midsummer, though sporadic blooms may appear afterward. These shrubs form next year’s flower buds in late summer or early fall as the days get shorter and temperatures cool off. To reduce the risk of removing these buds, prune just as the flowers begin to fade. Often, the earlier you get it done after bloom, the quicker the shrub can recover, producing more and larger blooms next season.

1. To tidy up, remove old blooms

Gardeners who want to maintain a tidy appearance can snip off spent blooms just below the flower head and remove any wayward or straggly canes at the soil line.

2. To improve vigor, remove the oldest canes

When a hydrangea gets old and woody, it can produce smaller blooms. Regular removal of a few of the oldest canes at the soil line can keep the shrub vigorous, producing large and abundant flowers. The same method can keep a shrub from getting too tall by targeting the tallest canes for removal.

 

Watch a video on pruning bigleaf hydrangeas

Almost everybody is enchanted by the large, mophead blooms of bigleaf hydrangea (Hydrangea macrophylla and cvs. , Zones 4–9). And it seems that almost everybody who grows these flowering shrubs has questions about pruning them. The thought is often that, because they are shrubs, they must need to be pruned. Some gardeners also think that cutting back their hydrangea might make it bloom. Neither of these thoughts is correct. Bigleaf hydrangeas grow just fine without any pruning, and making your cuts at the wrong time can actually remove the flower buds you are hoping to get.

Bigleaf hydrangeas typically bloom on old wood, meaning the flower buds are on the growth produced the previous season. If you prune them before they flower, you will be removing the flower buds. Many newer varieties actually produce buds on old and new wood, so pruning too early doesn’t stop the whole show, just a good portion of it. But if your hydrangea isn’t blooming, poorly timed pruning is often the culprit. The best time to cut back a bigleaf hydrangea is just after it is done blooming. The shrub then has ample time to set new growth and harden off before winter.

If you do decide you need to prune your bigleaf hydrangea, this video will give you the information you need to time your cuts correctly and identify where to make them on the shrub. The only tools you will need are hand pruners and perhaps a pair of loppers to reach down into the hydrangea. Also, be sure to wear some safety glasses. You might not think they are cool, but it is very easy to poke your eye on a stem as you are trying to see down into the shrub. And a poke in the eye is never cool.

So stay safe, time it right, and enjoy your shrub.

Hydrangeas that bloom on new wood

Panicle hydrangea. Photo: courtesy of provenwinners.com

Smooth hydrangea. Photo: Michelle Gervais
  1. Panicle hydrangeas (H. paniculata and cvs., Zones 4–8)
  2. Smooth hydrangeas (H. arborescens and cvs., Zones 4–9)

Cut back these shrubs in late winter before new growth begins

Because they need to grow and set buds the same year that they bloom, shrubs that flower on new wood generally start blossoming later than old-growth bloomers, beginning in midsummer and continuing until the first frost. These shrubs are forgiving if pruning is not done at a certain time as long as you avoid pruning when the flower buds are opening.

1. To get bigger flowers, cut them all the way back

In late winter or early spring, these shrubs can be cut all the way back to the ground. Smooth hydrangeas will produce much larger blooms if pruned hard like this each year, but many gardeners opt for smaller blooms on sturdier stems.

2. To reduce flopping, leave a framework of old growth

Some hydrangeas’ branches often fall over under the weight of their blooms, especially after overhead irrigation or after a good rain. One way to alleviate this flopping is to cut the stems to a height of 18 to 24 inches to provide a sturdy framework to support new growth.

 

—Janet Carson is the horticulture specialist for the University of Arkansas Cooperative Extension Service.

Photos, except where noted: Steve Aitken

Illustrations: Chuck Lockhart

How, When, Where, and Why to Prune or Cut Back Your Hydrangeas

Hydrangeas can range in size, shape, and color, which is actually some of the appeal of these luscious shrubs. Still, many Hydrangea lovers wonder if they should prune or cut back these plants. The last thing anyone wants is to stunt the growth of their beautiful blooms. 

Most Hydrangeas don’t typically require pruning, but there are some situations where it may be appropriate. If the shrub has gotten too big for its growing area or needs a bit of a haircut, then you may want to snip off dead branches. However, pruning at the wrong time can prevent next year’s blooms.

Throughout the rest of this article, I’ll discuss some reasons you may choose to prune your Hydrangea. I’ll also explain how, when, and where to prune your shrub and ease your concerns about next season’s blooms. 

Do Hydrangeas Need to Be Pruned?

Unlike many other flowering shrubs, most Hydrangeas don’t automatically need to be pruned. However, some types do benefit from pruning, so it’s important to know what variety you have. 

In a perfect world, you would plant your Hydrangea and let it flourish. It’s a good idea to always try to plant these beauties in a space that’s big enough for the bush to grow to full size without needing to be cut back and reined in. 

However, sometimes we get the spacing wrong. If you’re not the one that initially planted the Hydrangea, or you just misjudged the space you allotted, you can control the size somewhat with pruning. But first, you’ll need to know if the plant is an old wood or new wood bloomer.

The Difference Between Old Wood and New Wood in Hydrangeas

There are two distinctions among Hydrangeas that you need to know and understand before taking the clippers to your shrubs – those that bloom on old wood and those that bloom on new. The most common varieties in residential gardens are old wood bloomers.

Old wood varieties include Big Leaf, Oakleaf, Mophead, and Lacecap. Chances are that the Hydrangea in your yard is one of these types unless you have an “endless summer” variety which blooms on both old and new wood to extend the blooming season.  

Old Wood Hydrangeas

Old wood bloomers do just what you probably expect – they bloom on old wood. Stems are known as “old wood” if they’re the same stems on the plant during the previous summer before the growing season. 

These plants start preparing for the following year’s blooms in the late summer, typically between August and September. Flower buds grow in the tips of old wood stems and wait patiently for the following year’s warm months. Buds along the lower parts of the stem also develop over this long period. 

Making the mistake of pruning your old wood Hydrangea at the wrong time can result in a season with no blooms. 

New Wood Hydrangeas

The other type of Hydrangea is new wood bloomers, which will develop buds on the current growing season’s “new” wood. Unlike old wood, these varieties won’t have their flower growth stunted if you get overzealous with the shears. 

New wood varieties include Smooth and Panicle types, commonly known as PeeGee and Annabelle Hydrangeas.  

For more information on how to tell the difference between old wood and new wood blooming Hydrangeas, check out this article. 

Reasons to Prune Your Hydrangea

Despite their reputation for being low maintenance and needing very little human intervention, there are some circumstances where pruning your Hydrangea is a good idea. Whether you want to make your garden a little tidier or your Hydrangea doesn’t have the look you want, pruning may be the answer.

Keep in mind that all Hydrangeas look dead in the winter, so it’s important to understand the situations that call for cutting. Let’s discuss the five main reasons for pruning your Hydrangea. 

Reason #1 – Hydrangea is Woody

Aside from the show-stopping blooms, much of the appeal of a Hydrangea shrub is its lush, green appearance. However, sometimes these plants can start to look woody and seem to be like more sticks than foliage. 

If your Hydrangea is woody, it could be due to cold damage from harsh winter months, causing some of the stems to die and leaving behind twigs in the spring instead of lush green leaves. Another reason could be the natural aging process of the plant when older stems become less productive and stop spending energy on growing new leaves and blooms.

If your Hydrangea gets this woody look, pruning can help it regain its previous healthy appearance. These plants will typically bounce right back after getting a little TLC and will stay beautiful for many, many years to come.

However, you should keep in mind that if your Hydrangea is woody because of another issue, like stress or insufficient nutrients, you will need to correct the problem to improve the shrub’s appearance. Pruning alone will not resolve the deeper issue that’s causing the woodiness. 

Along with the trim, make sure that your Hydrangea gets enough water (at least 1″ per week), sufficient sunlight, and enough soil nutrients. You can consider using soil additives or some organic mulch to give the bush a boost. For more information on dealing with woody Hydrangeas, read this article.

Reason #2 – Hydrangea is Leggy

A leggy Hydrangea, also sometimes referred to as “spindly,” is one that looks top-heavy and where the blooms tend to droop down to the ground because the stems are too weak to give adequate support.

Legginess is a common problem for Annabelle Hydrangeas and other varieties with heavier blooms. It can drastically alter the appearance of your shrub, resulting in a look that’s not quite what you imagined when you planted your Hydrangea.

Though the root cause of legginess is that the plant isn’t getting enough sunlight, this effect can also occur if the Hydrangea doesn’t have enough support around the base of the plant. 

If you’ve already checked for other plants or structures that could be blocking the Hydrangea’s sunlight, or if it’s an established plant that you’re unable to move, the next step is to make sure it has a solid base to support its heavy blooms. (You can also check out this article for instructions and tips for transplanting a mature Hydrangea).

You can improve the base structure for your Hydrangea by pruning to encourage new growth to add additional support. If your Hydrangea is still young, it should be pruned or pinched off to help it reach its full growth potential.  

Remember, wherever you cut or pinch off one growing tip, you’ll get two more stems! It’s an easy and effective way to grow additional supports and expand the plant’s base. More healthy stems will provide greater support to hold up those big, beautiful blooms year after year.

For more help with your leggy Hydrangeas, click here.

Reason #3 – You Have a Panicle or Smooth Hydrangea

Panicle and Smooth Hydrangeas are some of the few common Hydrangea varieties that bloom on new wood. These shrubs that bloom on new wood are more prone to the legginess problem I just described than the old wood varieties because the stems are typically less robust than their old wood counterparts.

Panicle Hydrangeas (H. paniculata) include PeeGees, and Smooth Hydrangeas (H. arborescence) include Annabelles. These new wood bloomers can be pruned to the ground each fall and come back in the spring with lush foliage and beautiful blooms. 

However, you should remember that excessive pruning (especially if repeated each year) can cause the new growth to become weaker and the blooms less bountiful. That’s why it’s a good idea to be a bit more selective with your pruning by only cutting back dead and crossing stems.

The goal of pruning Panicle and Smooth Hydrangeas is to strengthen the support and maintain the aesthetic quality of the plant. Some Panicle Hydrangeas can begin to look overgrown if not cut back some.

PeeGee Hydrangeas are also the only type that can be pruned into a tree form. If that’s something that you’re interested in trying, you should cut back all the branches around the middle, leaving only the trunk and the top branches to create the tree shape. However, achieving the desired look can take many years, and it may not be very pretty in the meantime.

Reason #4 – You Want to Cut Back Old Blooms

Hydrangeas produce some of the most beautiful blooms that you’ll see on a garden shrub. However, once they become spent, they are much less appealing. Chances are, you’ll want to remove these dead or faded blooms to make room for more pops of color, or just because they’re a bit of an eyesore.  

Removing spent flowers is known as ‘deadheading,’ and it’s technically not the same as pruning, but it still involves cutting or trimming the shrub. It’s also an important part of Hydrangea maintenance, so I think it’s good to mention it here.

There are benefits to deadheading spent blooms besides just maintaining your shrub’s appearance. Hydrangea blooms are big (comparatively speaking) and quite complex, so they consume a lot of energy and resources. Removing them once they’re starting to fade allows your Hydrangea to use its energy to produce new growth.

How to Deadhead Hydrangea Blooms

Just when you thought, “this part should be simple,” it turns out that even removing dead blooms requires a little bit of know-how for ideal results. Where you perform your cut depends on the time of year. 

During the summer, you can snip off the bloom and its entire stem. If you cut the bloom while it’s still got some life in it, these are great to stick in some water for your home. If you’re interested in getting Hydrangea cuttings for vases, check out this article.

However, after the summer bloom season has begun to wind down (August or later), you should determine if your Hydrangea is old wood or new wood bloomer. If it’s an old wood bloomer, remove only the bloom, snipping or pinching it off just below the base of the flower. If you’re unsure, it’s a good idea to just take the flower to avoid accidentally removing any of your buds developing for next season. 

Reason #5 – You Want to Keep Your Hydrangea Small

Hydrangeas tend to grow to their desired size (or at least try to) even if you cut them back. In fact, they’re so stubborn that pruning usually causes the new growth to come back bigger, stronger, and bushier than before. 

However, if you wish to keep your Hydrangea small and manageable, it can be done with careful pruning at the right time. Just remember that you’ll have to continue this task year after year to maintain the small size and your desired shape.

To maintain a Hydrangea’s size or shape, you should use “heading cuts” to shorten branches or redirect the growth in your preferred direction. To perform this cut, make sure that the highest point of the angled cut is about ¼” above a bud. Cutting too close or too far from the bud will not produce the intended results.

When Is the Best Time of Year to Prune Hydrangeas?

When you should prune your Hydrangea depends on what type of plant you have. Pruning your Hydrangea at the wrong time could result in a sad summer with no blooms! The best time to prune is either just before or just after your Hydrangea’s growing and flowering period. 

Take a look at this simple chart to help determine when you should cut back your Hydrangea: 

Hydrangea VarietyOld or New WoodWhen to Prune
Bigleaf, H. macrophyllaOld wood (after one year)Summer, as blooms begin to fade (July-August)
Oakleaf, H. quercifoliaOld woodSummer, after flowering (July-August). After 5 years, cut back ⅓ of stems to the ground each summer after blooming.
Panicle, H. paniculata(PeeGee types)New woodLate fall or winter, before spring growth
Smooth, H. arborescens(Annabelle types)New wood Late fall or winter, before spring growth
Mountain, H. serrataOld woodSummer, after flowering
Climbing, H. anomalaOld woodSummer, after flowering. Do not prune during the first 2-3 years of planting.
“Endless Summer” & “Let’s Dance” cultivarsOld wood and new woodPrune in spring, remove spent blooms. After 5 years, cut back ⅓ of stems to the ground each summer after blooming.
Source: Almanac.com & University of Connecticut 

How to Prune a Hydrangea

After you’ve determined if, and more importantly, when your Hydrangea needs to be pruned, it’s time to get your hands dirty. It’s good to start with some high-quality shears, and this bypass pruner by Fiskars is always my go-to. Always clean your shears thoroughly before use.

Pruning Old Wood Bloomers

To prune your old wood Hydrangeas, thin out the stems to help maintain the shrub’s size and shape. Only remove dead stems or branches that are crossing one another. To tell if a branch is dead, you can scrape it with your fingernail to see if there is live growth underneath. If you see any green, the branch is alive.

If your Hydrangea is looking weak and unhealthy, or if you need to remedy a problem with legginess or woodiness, you may need to do some additional pruning. To rejuvenate your shrub, cut the oldest branches down to the ground (during the summer). Never cut back more than ⅓ of the stems during a single season. You can repeat this process the following year if needed to remove another ⅓ of the old growth.

Pruning New Wood Bloomers

Hydrangeas that bloom on new wood can be pruned in the fall or winter without the risk of removing next season’s blooms. You can also remove a significant amount of stems, and your shrub will come back beautifully in the spring. 

For best results, prune Annabelle, PeeGee, and Limelight Hydrangeas in the late fall or winter. It’s a good idea to cut down any dead or crossing stems. 

Should a Hydrangea Be Cut to the Ground?

Most Hydrangeas don’t need to be cut down to the ground, however certain varieties may benefit from this pruning technique. 

Smooth Hydrangeas should be pruned in late winter/early spring, and they can be cut down to the ground if you wish. Pruning will encourage new growth in these varieties and can help increase flowers. 

Panicle Hydrangeas should not be cut down to the ground; instead, just remove up to ⅓ of the oldest stems to improve new growth and blooms support.

If you decide to cut your Hydrangea down to the ground, this practice shouldn’t be repeated every year. Continued drastic pruning can cause weakening over time.

Will Hydrangeas Rebloom After Pruning?

Hydrangeas that bloom on new wood will rebloom after pruning because the flowers develop on the current season’s growth. This gives you a little more room for error on the timing. However, Hydrangeas that bloom on old wood may not rebloom after pruning for at least the next year. 

By referring back to the specified times that you should prune each type of Hydrangea, you can ensure that you don’t mistakenly lop off your upcoming buds that are developing in the Hydrangea’s stems.

Putting It All Together

The biggest takeaway from this article is that knowing what variety of Hydrangea is in your garden is essential. Whether it blooms on old wood or new wood makes a huge difference in how you should care for it. 

Overall, Hydrangeas are pretty low-maintenance, and you get a lot of benefits with minimal effort. However, there may be some circumstances where you need to cut back or prune your shrub. In that case, you can check out the information in this article to make sure you prune your plant at the right time to get the best result. 

Just remember that if you do happen to cut back your Hydrangea at the wrong time, you might end up with a bloomless summer, but it’s not the end of the world. Just continue to give it plenty of water, and it will come back even better and more beautiful the following season. 

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