When to Trim Boxwoods and How to Do It the Right Way

Boxwoods are hardy evergreen shrubs that are valuable for forming borders for driveways and walkways for formal and contemporary homes. Learn when to trim boxwoods and how best to do it for a neat, low-maintenance look.

Why Boxwoods Need Trimming

To grow properly, boxwoods need regular pruning and thinning. Boxwood shrubs are so dense that it’s difficult for leaves on the interior to receive light and air. Trimming and pruning open the plant and allow light and air circulation.

When boxwoods fail, it’s often because the plant hasn’t been adequately trimmed. Dense foliage can result in fungus, blight, or pest infestation.

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When to Trim Boxwoods

The best time to prune or trim evergreen shrubs like boxwoods is mid- to late-spring. Trimming too early in the year can kill the plant in cold climates.

Another light trimming is allowed by mid- to late-summer. More trimmings after this time will be detrimental, as the boxwoods won’t be able to grow new leaves for winter protection.

Avoid trimming or pruning boxwoods during the fall or winter, though dead wood can be clipped and removed in any season.

How to Tell If Boxwoods Need Trimming

Three ways to know it’s time to trim or prune your boxwoods:

• It’s spring: Cleaning up and trimming your boxwoods is an annual event, with most of the work happening in the spring.
• There’s fungus: Curled or undersized leaves may indicate fungus, which should always be trimmed.
• You see overgrown branches: Stray branches you missed in an earlier trimming can be cut. But don’t do an overall trimming at the wrong time of year.

Tools for Trimming Boxwoods

Hedge shears help you prune and trim boxwoods, while electric trimmers are only for trimming broad swaths. While it’s best to have both, buy a premium pair of hedge shears if you have to choose just one.

Hedge Shears

Manual garden hedge shears look like a large pair of scissors, and they let you prune and trim shrubs like boxwoods.

The extended handles reach to the top or around shrubs. Hedge shears cost $25 to $50.

Electric Hedge Trimmer

With blades 18 to 24 inches long, electric hedge trimmers are invaluable for paring down boxwoods’ large, flat sides and tops. Most blades can handle branches up to 3/4-inch diameter, perfect for boxwoods. 

Cordless electric hedge trimmers are easier to maneuver than corded models and let you reach all areas of your yard. Their lithium-ion batteries last an average of 30 to 60 minutes.

Boxwood Trim Styles

There are two styles of trimming boxwoods: either formal or natural.

Formal Boxwoods

Boxwoods are often trimmed into smooth planes and straight lines that create geometric shapes. This style is used with traditionally styled homes and gardens but can be used wherever bold borders are desired.

Formally trimmed boxwood appears to be cut at 90-degree angles, but its shape is more like a pyramid: narrow at the top and wider at the bottom. The tilt isn’t noticeable, but it helps the entire side of the boxwood receive sunlight.

Natural Boxwoods

Boxwoods can be trimmed to follow the general shape of the plant. It’s a more natural look that avoids the manicured, topiary look. 

Pruning is the emphasis when naturally shaping boxwoods. Stray branches are trimmed and dead wood is removed. The surface can be finished smooth, much like the formal trim style, or left shaggy, for a casual look.

How to Trim Boxwoods in a Formal Style

To trim boxwoods, you need eight stakes as high as the boxwood plus another foot, a tape measure, twine or mason’s string, a hammer or mallet, hedge shears, and a hedge trimmer.

1. Trim stray branches: Clip long, stray branches with the hedge shears.
2. Measure the shrub: At one end of the shrub, measure its width at the bottom and top. 
3. Decide on the size: Plan the boxwood’s desired size and shape. For example, you may want it to be 3 feet wide at the bottom and 2 feet wide at the top. The 12-inch difference will be split between the sides. The height is typically greater than the width.
4. Place the inner stakes: Hammer the two inner stakes at one end of the shrub (for example, 2 feet apart). Go to the end of the boxwood and repeat. 
5. Place the outer stakes: Hammer the two outer stakes at the end of the shrub (for example, 3 feet apart). Repeat with two more stakes at the other end of the boxwood.
6. Run the inner strings: Tie the strings between the inner stakes and run them along the length of the boxwood. Place the inner strings at the desired height since they also represent the top of the boxwood.
7. Run the outer strings: Tie strings lengthwise between outer stakes. Place the strings at 6 inches high.
8. Trim the boxwood: First, use the hedge trimmer to trim the sides of the boxwood and then finish with the top. Be careful not to cut the strings or catch the trimmer blades in the stakes.

How to Trim Boxwood in a Natural Style

For this project, you will need hedge shears, a rake, and a set of gloves.

1. Clean off debris: Remove fallen leaves and debris on the top or sides of the boxwood. Reach debris in inaccessible areas with an old broom or rake.
2. Note the shape: Take note of the shrub’s natural shape and aim to follow its general contours.
3. Trim the long branches: First, cut the longest branches. Do this by reaching several inches into the shrub and cutting.
4. Toss clippings aside: Occasionally remove clippings from the boxwood and toss them in the compost container. Clippings left in the plant obscure the shape, making trimming more difficult.
5. Trim both sides: After cutting a few branches on one side, move to the other side for visual balance. Go back and forth during the entire trimming process.

Tips for Trimming Boxwoods

Trim your boxwoods to keep them healthy and attractive with these tips:

• Use quality tools: Use the best trimming tools within your budget, especially if you have a lot of boxwood shrubs.
• Sharpen the blades: Sharpen hedge shear blades once a year as you would sharpen scissors—with a sharpening stone or by having them professionally sharpened.
• Step back: When trimming, step back several times and view the boxwoods from different angles to better understand how the shape is coming along.
• Clean the tools: After each use, clean your garden tools and store them in a dry location.
• Clean the boxwoods: After trimming, clean the clipped leaves from under the boxwood, on top, and the sides.