How To Prune Overgrown Arborvitae

You can prune overgrown arborvitae, but only if you do it the right way and at the right time of year.

It’s a common misconception that these dense evergreens can handle a hard haircut like some other shrubs, but the truth is that arborvitae have very specific growth habits that dictate how much you can safely remove.

If you’ve been staring at a towering, sprawling arborvitae that’s blocking your windows or crowding your walkway, you might be wondering how to prune overgrown arborvitae without killing it.

In this post, we’ll cover the safe methods for pruning overgrown arborvitae, the best timing for the job, and the critical mistakes you absolutely need to avoid.

Let’s dig in and get your hedge back under control.
 

How to Prune Overgrown Arborvitae Safely

The safest way to prune overgrown arborvitae is to focus on the green outer foliage and never cut into the brown, woody interior.

This is the golden rule because arborvitae do not regrow from old wood.

Once you cut back to bare branches that have no green needles, those sections will stay bare forever, leaving you with ugly, permanent dead spots.

So when you prune overgrown arborvitae, you’re really working with the living green layer on the outside of the plant.

Here’s the best approach to get the job done without causing long-term damage.
 

1. Assess the Extent of the Overgrowth First

Before you even pick up your shears, take a good look at how overgrown your arborvitae really is.

If it’s just a few inches too wide or a foot too tall, you can easily prune overgrown arborvitae back to a manageable size.

But if the plant has doubled in size and is now completely covering a window, you may need to consider a more drastic approach.

Just remember that if the overgrowth means you have to cut back into the brown center, you’re going to end up with permanent gaps.

In that case, you might be better off replacing the plant entirely rather than trying to prune overgrown arborvitae that has exceeded its space by too much.
 

2. Use the Right Tools for a Clean Cut

The tools you choose will make a huge difference in how well your arborvitae recovers from pruning.

For soft, green growth, a sharp pair of hand pruners or hedge shears is perfect.

If you are tackling thicker branches that are more than half an inch in diameter, you’ll want loppers or a pruning saw.

The key is to ensure your tools are sharp and clean.

Dull blades can crush the stems, which invites disease and slows down the healing process.

And always sterilize your tools with rubbing alcohol before you start pruning overgrown arborvitae to prevent spreading any fungal infections.
 

3. Prune in the Right Shape

Arborvitae naturally grow in a pyramid or columnar shape, with the top being narrower than the bottom.

When you prune overgrown arborvitae, you want to maintain that natural taper.

This means you should keep the bottom of the plant wider than the top.

If you cut the top wider than the bottom, you’ll block sunlight from reaching the lower branches.

This lack of sunlight will cause the lower foliage to die off, leaving you with a thin, bare base that looks pretty sad.

So always step back and check your angles to keep that natural, healthy triangle shape.
 

4. Don’t Cut More Than One-Third

As a general rule, you shouldn’t remove more than one-third of the plant’s total foliage in a single pruning session.

Removing more than that causes severe stress to the arborvitae and can shock the root system.

If your arborvitae is severely overgrown, it’s much better to spread the pruning over several seasons.

This slow approach allows the plant to recover between trims and keeps it healthy and green.

So when you prune overgrown arborvitae, be patient and stick to that one-third rule to avoid killing your shrub.
 

The Best Time to Prune Overgrown Arborvitae

The best time to prune overgrown arborvitae is in late winter or early spring, just before the new growth begins.

Pruning at this time gives your arborvitae the entire growing season to recover and fill in any cuts you made.

Late spring and early summer also work well, but you need to be careful not to prune during a drought or heatwave.

The worst time to prune overgrown arborvitae is in late summer or early fall.

Pruning then encourages new, tender growth that won’t have time to harden off before winter arrives, which can lead to frost damage.

So if you want to prune overgrown arborvitae and see it bounce back quickly, aim for that early spring window.
 

1. Light Maintenance Trims Throughout the Year

While the major renovation should happen in early spring, you can do light maintenance trims throughout the growing season.

If you just want to tidy up a few stray branches that are sticking out, you can do that anytime between spring and late summer.

These small trims won’t stress the plant much, and they help keep the arborvitae looking neat.

Just avoid any major shaping during the heat of summer, as the sun can scorch the newly exposed inner foliage.
 

2. What to Do With Severely Neglected Arborvitae

Sometimes you come across an arborvitae that has been ignored for years and is just a mess of woody, brown branches with a little green on the very tips.

If you try to prune overgrown arborvitae that is in this condition, you’ll be left with nothing but bare wood.

In this case, the arborvitae is beyond saving with simple pruning.

Your best bet is to remove the entire plant and replace it with a new, appropriately sized arborvitae that won’t outgrow its space.

It’s a tough call, but it’s better than staring at a half-dead, unsightly bush for years.
 

Common Mistakes to Avoid When Pruning Overgrown Arborvitae

There are a few common mistakes that gardeners make that can turn a simple pruning job into a disaster.

Avoid these pitfalls so you can prune overgrown arborvitae with confidence.
 

1. Cutting Into the Dead Zone

We’ve mentioned this before, but it’s worth repeating because it’s the most common and deadly mistake.

The dead zone is the brown, interior part of the arborvitae where no green needles grow.

This zone will never sprout new growth.

If you cut back into this area, you’ll have a permanent hole in your hedge.

Always keep your cuts in the green, outer foliage, and you’ll be safe.
 

2. Topping the Tree

Topping an arborvitae means cutting off the top of the tree to reduce its height.

This is a terrible idea because it ruins the natural shape and leaves an ugly, flat stump at the top.

The tree will try to send up new shoots from below the cut, but these will be weak and look unnatural.

Instead of topping, if your arborvitae is too tall, consider replacing it with a shorter variety that fits the space better.
 

3. Pruning Too Late in the Season

Pruning overgrown arborvitae in the fall is a recipe for disaster.

The new growth that appears after a fall pruning won’t have enough time to mature before the first frost.

This tender growth will get nipped by the cold, turning brown and ugly.

Stick to the early spring or late spring timeframes for any major pruning work.
 

So, Can You Prune Overgrown Arborvitae?

You can prune overgrown arborvitae, as long as you’re working within the green growth and not cutting into the brown, dead wood.

The key to success is understanding that these evergreens don’t regenerate from bare branches, so your pruning strategy has to be conservative and thoughtful.

By pruning in early spring, using sharp tools, and maintaining the natural pyramid shape, you can bring your overgrown arborvitae back to a healthy, beautiful size.

Just remember the one-third rule and never fall for the temptation to top the tree.

Hope this helps you get your arborvitae back under control for good.