This general guide will teach you how to prune hydrangeas. There are many varieties of hydrangeas, and certain bushes need specified pruning techniques for proper growth and flower production. Depending on what particular type of hydrangea you have, you’ll need to adopt a different pruning technique.
Hydrangeas are often used as a border, a statement piece, or are planted in containers for beautiful, showy flowers through the summer. They are not picky plants but they need proper pruning to keep them as healthy as possible and have big showy blooms year after year.
Don’t worry, we’ll explain everything and let you know the proper pruning that’s needed for your type of hydrangea. So keep on reading as we go over everything you need to know about pruning your hydrangeas.
Table of Contents
How to prune Hydrangeas
Old Wood And New Wood
Hydrangeas will bloom on either new or old wood. Learning the difference between these two will determine how to trim your hydrangea. Pruning at the wrong time, or pruning too aggressively will hinder blooms next year.
Hydrangeas that bloom on new wood include smooth and panicle hydrangeas. These produce flower buds on new, green growth in the early spring.
Old wood hydrangeas produce flower buds on brown, woody stems and include climbing hydrangeas, big leaf, and oak leaf hydrangeas. They produce flower buds during the later part of summer, and they bloom the following growth season.
If you prune these hydrangeas too aggressively, or in early spring, you could end up cutting off all that year’s flowers. You’ll get big showy foliage, but that’s about it until next year.
Pruning New Wood Hydrangeas
Pay attention to how your hydrangeas grow each year if you’re not sure what specific cultivar you have in your yard. Early spring buds that hurry up and sprout big clusters of flowers mean you have a new wood hydrangea.
The best time to prune these bushes is in late winter, or very early spring. Leaving the old, dried out flowers throughout winter may give your yard some visual appeal. They make great photographs when the brown flowers are covered in a thick layer of frost or a light blanket of snow.
Before you start the pruning process, make sure you have a good pair of clean and sharp pruning shears. If you don’t have any, you can find some here: Gonicc 8″ Professional Premium Titanium Bypass Pruning Shears.
Clean them with a solution of bleach and water to make sure there aren’t any bacteria or fungal spores that could introduce infection. Use a mixture of 5 parts water to one part water, or carefully wipe them down with some isopropyl alcohol.
With your gloves and shears, inspect the plant. In early spring or late winter, you should be able to see some small buds on the branches. Look for strong, tightly folded buds on a growth node and trim the branch just above the buds.
Depending on the height and the age of the shrub, you may be removing as little as 6 inches, or over a foot. Take your time and trim each of the branches, leaving behind the new growth and the healthy buds.
While you are trimming the hydrangeas, look for branches that are completely dead, or rubbing on other branches. When a plant’s branches rub together, they can produce wounds that can introduce infection or attract pests.
When you find a couple of branches that are rubbing, try to cut away the smaller branch. If you have to, go ahead and cut it away to the ground just to prevent it from growing back and rubbing again later on.
Also, remove any dead branches or any branches that look too small or infected. This will help the plant focus on healthier growth.
Pruning For Shape And More Aggressive Pruning
Occasionally you may have to get more aggressive with your pruning on these types of hydrangeas. Maybe you want to keep a certain shape, or you just need to trim it back a bit because it’s getting rather unruly.
Do this aggressive pruning while the plant is still dormant. Again, attempt this during late winter or early spring, before you start seeing leaf buds opening up. You can trim these hydrangeas pretty far back if you need a restart.
New growth hydrangeas can be cut down to about a foot above ground without much harm. They will bush back out and still produce some flowers, though probably not as much this year as you had last season.
If you are cutting these types of hydrangeas down to keep them smaller, be aware that they will often grow back—near to their original size—the same year. If this hydrangea has just gotten too big, you probably need to dig it up and move it somewhere else, and find a smaller variety to replace it.
Pruning Old Wood Hydrangeas
Bigleaf, oakleaf, and climbing hydrangeas all produce flower buds in summer that harden off and survive throughout the winter for big blooms the following spring. These are old wood hydrangeas and they require more finesse when pruning.
If you go too aggressive on these bushes, you could prevent any blooms the following spring. The best time to prune these hydrangeas is after the flowers have bloomed and have started to fade.
Don’t wait until fall or winter to prune old wood hydrangeas, as you could accidentally cut off all the tiny flower buds.
All you want to trim off these hydrangeas are the flower heads. Basically, you are just doing a “deadheading.”
While you are trimming these types of hydrangeas, continue to be on the lookout for rubbing branches, sickly looking, and dead branches. Go ahead and remove any of these culprits for the health of the plant.
Since nearly all of the older growth looks like it could be dead, you can do a scratch test to find out if it’s dead or not. Take your fingernail and gently scratch away a small section of the top layer on the branch.
Green underneath, obviously means it’s still alive and doesn’t need to be cut off. If it’s brown or grey under, it needs to be cut off. You can also wait until the next spring when the hydrangeas are just starting to bud out.
Check any branches that don’t have any buds on them and cut them back to the original stem or to the ground.
How To Prune Reblooming Hydrangeas
These plants of course are the obligatory exception. Hydrangeas such as reblooming bigleaf or reblooming mountain hydrangeas produce flowers on both new and old wood.
Ugh, how do you trim a hydrangea that blooms on everything? Just trim them as if they are old wood bloomers. In the summer, once the flowers are spent, trim off the dried out flower heads.
You can also trim off any rubbing or dead branches in fall or in spring once the plants are starting to bud.
What Happens To Hydrangeas That Aren’t Trimmed?
While it’s not absolutely necessary to trim hydrangeas, when they aren’t trimmed occasionally, they will grow spindly and unhealthy. They will eventually become a bedraggled mess of dead, woody stems with some leaves and flowers.
Over time the flowers shrink in size and look spindly. One of the biggest reasons hydrangeas don’t bloom at all is because they are not properly trimmed.
Hydrangeas that don’t get trimmed every now and again are also at an increased risk of infection and pest invasion. Healthier bushes not only produce bigger flowers, and look better overall, but they don’t get sick as often.
Trimming dead growth, rubbing branches, and keeping them neat is the best way to encourage new, healthy growth. You’ll get bigger, broader leaves, and flashier flowers.
Does Deadheading Hydrangeas Produce More Blooms?
Unfortunately, this practice of removing spent flowers to encourage new flowers doesn’t work all that well for hydrangeas. Whether they are new wood or old wood flower producers, hydrangeas don’t produce more flowers in the same growth season.
Old growth hydrangeas produce new flower buds after growing their flowers, but they overwinter and then bloom the following spring and summer.
New wood growth hydrangeas produce flower buds in late winter and early spring. These flowers start blooming when the plant emerges from dormancy.
Flowers like roses and butterfly bushes will continuously produce more blooms after snipping off the dead ones, but this doesn’t apply to hydrangeas.
You can get new flowers on reblooming varieties of hydrangeas, but deadheading doesn’t work on these either. Reblooming hydrangeas rebloom because they produce flowers on both new growth and old growth branches.
For those looking for a cleaner look in their garden, you can certainly deadhead them to get rid of the dried out flowers. Just don’t expect new, colorful buds to come back later in the year.
A Common Hydrangea Trimming Misconception
There is a common misconception about trimming hydrangeas. That is you can prune these shrubs throughout the growing season to keep them short and compact.
This practice shouldn’t be followed or you’ll end up cutting off all of next year’s flower buds. If you need to trim your hydrangea down because it’s getting too big, you can cut them back but understand that you may not get any flowers the following season.
They will grow back the second year and probably be more bushy and have even more flowers though.
Hydrangeas that produce flowers on new wood can be trimmed back more to keep them smaller, but they will quickly fill back out and grow close to their original size the next growth season.
Frequently Asked Questions
Can I prune hydrangeas in the fall?
In areas that get a lot of snowfall in the winter, leaving the dried flower heads on hydrangeas may not be the best practice. A lot of snow will accumulate on the dried flowers and snap branches. We don’t want that because it could hinder next year’s flower production as well as the overall health of the plant.
If you’re worried about heavy snowfall breaking off branches, you can certainly deadhead your hydrangeas in the fall. Come spring, you can trim them a little more (if they are new wood hydrangeas such as panicle or smooth leaf varieties).
How far back can I trim my hydrangea?
Depending on the type of hydrangea and your ultimate end goal, you can trim your hydrangea slightly, or be more aggressive with the pruning. For new wood hydrangeas, you can trim them back to about a foot above the ground without harming the bush. You probably won’t get many flowers that year, but if you need a reset, or it has gotten spindly and unhealthy looking, this will help.
For old growth hydrangeas, it’s not recommended to trim them back beyond deadheading. Unless you need to shape it or cut back some long growth, old wood hydrangeas only require a light trim each year.
Can I cut my hydrangea to the ground?
Once your hydrangea is well established and has been in the ground a few years you can trim it down low if needed. While some may still come back after getting trimmed to the ground, it’s best to leave some growth above ground. If your hydrangea needs a very aggressive trimming, cut it down to about a foot above ground when it’s dormant.
Final Thoughts On Pruning Hydrangeas
Pruning your hydrangeas shouldn’t be daunting or difficult as long as you know what kind of plant you have. Hydrangeas produce flowers on either new wood or old wood.
Hydrangeas that produce flowers on new wood include smooth hydrangeas and panicle hydrangeas. Old wood growth hydrangeas include bigleaf, oakleaf, climbing, and mountain hydrangeas.
New wood hydrangeas should be trimmed in winter or early spring, just above new flower buds. Hydrangeas that produce flowers on old wood can be trimmed in summer right after the flowers are spent. Any aggressive trimming may result in fewer flowers the next year.
Finally, reblooming hydrangeas produce flowers on both new and old wood. To keep these bushes blooming, just trim off the old, dried up flowers at the end of summer.
We hope this has cleared up any confusion, and has you ready to trim your hydrangeas with newfound confidence.
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