Pruning 101: How to Trim Bushes, Hedges, and Shrubs

Your grass isn’t the only thing that needs an occasional trim if you’re trying to keep your landscape looking its best. Your plants also need some care. Pruning 101 explains how to trim bushes, hedges, and shrubs to keep them looking their best and growing strong and healthy.

Giving your plants a much-needed haircut can feel daunting. You might not turn into a topiary master, but you’ll definitely have the know-how to bob the boxwoods, lop the lilacs, prune the privet, and shear the spirea.

Here’s the answer to these landscaping dilemmas that keep cropping up:

Why Prune?

Pruning is both a growth retarding process and a bud-invigorating process. Buds on a pruned plant are exposed to more sunshine, and that sunshine encourages new growth and leads to larger leaves, flowers, and fruit.

There are many reasons to prune, says Patrick O’Malley, horticulture specialist with the Iowa State Extension in Van Buren County. “One is to shape the plant so it’s better-looking,” he says. “You can prune it to encourage flowering.”

Sometimes pruning keeps the good, formal look of a hedge, O’Malley said, and sometimes shrub trimming is needed to keep it from blocking a window or shading out other nearby plants. It can even encourage new growth in an old bush that’s not growing well.

A Science and an Art

“Pruning is considered by some horticulturists to be both a science and an art,” according to the University of California Extension’s guide to pruning. The science is in understanding the plant. The art is in seeing the beauty of the plant in how it responds to pruning, giving it a natural shape.

That’s right: A well-pruned landscape will look natural. “Good pruning is essentially invisible,” the guide says. If you must continually remove a lot of dead wood or trim shrubs that grow at a high rate, it may mean the plant is a bad fit for the landscape.

Before you Start to Prune

There are a few things you need to know and do before you start hacking at branches or giving your boxwoods a haircut. 

• First, know what you have. O’Malley recommends picking up an Extension publication on the particular type of bush, hedge, or shrub to figure out the appropriate pruning regimen.

• Second, make sure you have a landscaping plan. What do you want the landscape to end up looking like?
  
• Third, gather and sharpen your pruning tools.
  
• Finally, remove dead or diseased limbs first, followed by crossing branches that are rubbing against each other. Also, try to remove as many of the branches that are growing back toward the center of the tree or shrub, as they will eventually be crossing branches and will rub.

How to Trim Bushes

Bushes range from small single- to multi-branched plants. They can become unruly depending on your climate and their growing season, so it’s best to learn their growing habits and keep them in check.

Best Time to Trim Bushes

The Michigan State University Extension lists late winter or early spring as the best time to prune bushes — before the new growth starts up for the year. But in all cases, the wrong time to prune is high summer, after new growth has taken hold.

You can prune your bushes to shape them from March through July, but O’Malley warns most pruning should stop by August. After shaping, the tender new growth can be injured by the coming winter. But there are exceptions. Some plants can be pruned in the fall, especially native plants.

Flowering Bushes

Whether a plant flowers is an important factor, O’Malley explains, as different flowering bushes will look better when pruned before flowering while others, including lilacs, will look better when flowering naturally and pruned after. Find out when your plant flowers, and you’ll know when to prune.

How, When to Prune Typical Types of Flowering Shrubs
Flowering Shrub Type	Examples	When to Prune	How to Prune
Spring-blooming shrubs (bloom on old wood)	Lilacs, forsythias, azaleas, weigelas, traditional bigleaf hydrangeas	Prune immediately after they finish flowering in spring.	Remove one-third to one-fifth of the oldest stems every two to three years. Prune those oldest stems back to 2 inches above ground level.
Summer-blooming shrubs (bloom on new wood)	Smooth and panicle hydrangeas, diervilla (bush honeysuckle), potentillas	Prune during late-winter dormancy, right before spring bud break.
Everblooming shrubs (bloom on old and new wood)	Remontant or reblooming shrubs, such as Endless Summer hydrangeas	If you prune, prune right after spring flowering (the biggest flush of flowers) finishes.	Limit pruning to a minimum for maximum flowering. Thin and shape only as needed.

Source: When and How to Prune Flowering Shrubs

Spring-flowering bushes: Their flower buds are produced on the previous year’s growth (old wood). If your plant flowers before the end of June, it is considered to be spring-flowering.

Summer-flowering bushes: Their flower buds are produced on the current year’s spring growth (new wood). If your plant flowers after the end of June, it is considered to be summer-flowering.

The goal is to prune flowering bushes at a time to minimize damage to blooming, and that depends on when the plant blooms. When in doubt, check the Web for a guide to plants in your region or contact a local expert like an Extension agent, or someone at your local nursery.

Tools Needed

There are several tools you can use to trim bushes, but dull tools will create jagged cuts that are more prone to peeling or decay. “It’s good to have sharp tools, whether a pruning saw, loppers, or pruners,” O’Malley said. It is helpful to read tool reviews in case you need to go shopping for trimming tools.

• Powered or long-bladed shears: Can be used for shaping bushes
  
• Pruning shears or “clippers”: Best for branches between 0.25 and 0.5 inches
  
• Lopping shears: Best for branches up to 1.5 inches in diameter. A strong, lightweight tool, usually 16 to 30 inches long.
  
• Bypass-style clippers or loppers: For small cuts; blades overlap and slide beside each other when they cut
  
• Anvil style: Best for dead branches. The blade fits into a groove, but they tend to pinch. They are useful for cutting away entire branches that hand clippers can’t handle.
  
• Pruning saws: Good for the bigger stuff, anything greater than an inch in diameter. They have rough teeth that prevent gumming, and most cut on the pull stroke for safety.
  
• Pole pruners: Either saws or lopping shears on a long pole reach those high branches.

Best Way to Trim Bushes

If you have thick, leafy bushes to trim, an electric or gas-powered hedge trimmer is likely the best bet to keep the bushes neat and trimmed and thick with foliage. However, for long-term health and beauty, there are several types of cuts that work in unison for beautiful, healthy bushes.

• Thinning: These cuts remove undesired growth, cutting off entire branches at the point of origin to result in a more open plant. This openness lets more sunlight and air into the center of the bush, resulting in more interior growth (leaves) along the stem and less disease (due to increased air flow). Thinning cuts won’t stimulate excessive new growth.

• Heading: In contrast with a thinning cut, heading cuts remove only a portion of a branch back to a bud. In some plants, this stimulates excessive growth, resulting in an unwanted witches’ broom effect. Heading cuts may be valuable if you want to reduce the number of buds on a branch in order to create more vigorous growth (fruit or flowers) from the remaining buds.
  

• Shearing: These cuts are made to shape a bush without worrying about where the buds are. (Shearing is most often done with electric or gas hedge trimmers.) Plants chosen for this type of treatment usually have many buds close together. The cuts will end up near a bud anyway and encourage robust new growth but may reduce flowering.
  
  Shear bushes no more than once per year. Use thinning and heading cuts for long-term health and beauty.

Prune young plants in their first year or two within one foot of the ground so stems are shortened and new growth is promoted below the cut.

Both the University of California and Michigan State University recommend using the “three-cut method” for removing branches larger than one inch in diameter. It eliminates the weight of the branch before you make a final cut to prevent tearing.

1. Make a small cut into the bottom of the branch at least 1 foot away from the branch collar on the trunk.
   
2. Cut from the top down, just outside of the first cut, completing the cut all the way through and removing the branch.
   
3. As you support the branch, cut just above the branch collar to provide a clean cut near the trunk that won’t tear or break from the weight of the branch.

How to Trim Hedges

Hedges range from small to large plants grown closely in rows or geometric shapes. They are grown for privacy, as windbreaks, and aesthetically pleasing softscapes on your property. An unkempt hedge can become unruly and an eyesore, so it’s best to trim consistently.

Best Time to Trim Hedges

It’s great to trim hedges as needed during the summer months, but before you pick up the shears, check the main breeding season of birds in your area. Hedges provide secure nesting areas for many birds, and you wouldn’t want to disturb a brood. 

The best time to trim hedges, especially if you’re doing a hard prune, is before they break dormancy in early spring. The plant needs to direct its energy into the new buds, so trimming off unwanted branches helps it get a fresh start.

We’ve all seen forsythia bloom in early spring. It rebounds happily with a great haircut. Evergreens, such as boxwoods and hollies, take longer to fill in from a cut, so it’s especially important to trim them very early. Lilacs like a trim as soon as those lovely, fragrant flowerheads turn brown, getting them ready for the next year’s show.

If you are unsure about your hedges, check the Web for a guide to plants in your region or contact a local expert like an Extension agent, or someone at your local nursery.

Tools Needed

There are several tools you can use to trim hedges. Make sure they’re at their sharpest for clean cuts and oiled for the best performance.

• Powered or long-bladed shears: Can be used for shaping hedges
  
• Pruning shears or “clippers”: Best for branches between 0.25 and 0.5 inch
  
• Lopping shears: Best for branches up to 1.5 inches in diameter. A strong, lightweight tool, usually 16 to 30 inches long.
  
• Hedge trimmers: Good for powering through larger, established hedges while trimming and shaping

Best Way to Trim Hedges

For homeowners with hedges, an electric or gas-powered hedge trimmer is the best bet to quickly keep them neat and trimmed. You can also use pruning clippers, and some homeowners prefer these to hedge trimmers. There are several types of cuts you can make according to the look or height you want to achieve.

• Thinning: These cuts remove undesired growth, cutting off entire branches at the point of origin to result in a more open plant. This openness lets more sunlight and air into the center of the bush, resulting in more interior growth (leaves) along the stem and less disease (due to increased air flow). Thinning cuts won’t stimulate excessive new growth.
  
• Heading: In contrast with a thinning cut, heading cuts remove only a portion of a branch back to a bud. In some plants, this stimulates excessive growth, resulting in an unwanted witches’ broom effect. Heading cuts may be valuable if you want to reduce the number of buds on a branch in order to create more vigorous growth (fruit or flowers) from the remaining buds.
   
• Shearing: These cuts are made to shape a bush without worrying about where the buds are. (Shearing is most often done with electric or gas hedge trimmers.) Plants chosen for this type of treatment usually have many buds close together. The cuts will end up near a bud anyway and encourage robust new growth but may reduce flowering.
  
  Shear hedges no more than once per year. Use thinning and heading cuts for long-term health and beauty.

Power tool manufacturer Stihl offers advice on trimming different styles of hedges, saying the first step is to cut the sides of the hedge vertically in a sweeping arc-shaped movement. When cutting the top of the hedge, the trimmer should be almost horizontal, with a slight angle toward the direction of the cut.

Stihl recommends using scything movements to clear clippings from the top of the hedge as you go.

Prune young hedge plants in their first year or two within 3 to 5 inches of the ground so stems are shortened and new growth (shoots) are promoted at the plant’s base.

How to Trim Shrubs

Though bushes and shrubs are often used interchangeably, shrubs are widely considered woody perennials that live longer than two years. They are the staple of many landscape designs and benefit greatly from trimming in their flowering, growth, and structural beauty.

Best Time to Trim Shrubs

Non-flowering shrubs should be pruned in dormancy, in early spring. If you trim them too early or too late, their nutritional needs may be interrupted as they travel to the essential parts of the plant for the dormant season.

As with bushes, a shrub’s flowering time is also another important factor. Spring-flowering bushes and plants should be pruned right after flowering since their flower buds are produced on the previous year’s growth, not new spring growth.

Again, if your flowering shrub blooms before the end of June, it blooms on last year’s growth. If it flowers after the end of June, it blooms on new year’s growth. If you are unsure of your shrub’s flowering season, check the Web for a guide to plants in your region. You can also contact a local expert like an Extension agent, or someone at your local nursery.

Tools Needed

There are several tools you can use to trim shrubs. Avoid jagged cuts with sharp tools that are oiled and sharpened on a regular basis and kept in a dry location.

• Powered or long-bladed shears: Can be used for shaping shrubs
  
• Pruning shears or “clippers”: Best for branches between 0.25 and 0.5 inch
  
• Lopping shears: Best for branches up to 1.5 inches in diameter. A strong, lightweight tool, usually 16 to 30 inches long.
  
• Bypass-style clippers or loppers: For small cuts, the blades overlap and slide beside each other when they cut.
  
• Anvil style: The blade fits into a groove. They tend to pinch, but they’re useful for cutting away dead branches that hand clippers can’t handle.
  
• Pruning saws: Good for large branches, greater than an inch in diameter. They have rough teeth that prevent gumming and most cut on the pull stroke.
  
• Pole pruners: Either saws or lopping shears on a long pole to reach high branches.

Best Way to Trim Shrubs

You should consider taking more time and caution when trimming shrubs, as opposed to bushes. Shrubs are usually densely-branched and have thicker limbs. You can use all three types of cuts below to get the look you want to achieve.

• Thinning: These cuts remove undesired growth, cutting off entire branches at the point of origin to result in a more open plant. This openness lets more sunlight and air into the center of the bush, resulting in more interior growth (leaves) along the stem and less disease (due to increased air flow). Thinning cuts won’t stimulate excessive new growth.

• Heading: In contrast with a thinning cut, heading cuts remove only a portion of a branch back to a bud. In some plants, this stimulates excessive growth, resulting in an unwanted witches’ broom effect. Heading cuts may be valuable if you want to reduce the number of buds on a branch in order to create more vigorous growth (fruit or flowers) from the remaining buds.
  
• Shearing: These cuts are made to shape a bush without worrying about where the buds are. (Shearing is most often done with electric or gas hedge trimmers.) Plants chosen for this type of treatment usually have many buds close together. The cuts will end up near a bud anyway and encourage robust new growth but may reduce flowering.
  
  Shear shrubs no more than once per year. Use thinning and heading cuts for long-term health and beauty.

Prune young plants in their first year or two within one foot of the ground so stems are shortened and new growth is promoted below the cut.

As mentioned in the “Best Way to Trim Bushes” section, the “three-cut method” is great for removing branches larger than one inch in diameter and eliminating the weight of the branch before you make a final cut.

1. Make a small cut into the bottom of the branch at least 1 foot away from the branch collar on the trunk.
   
2. Cut from the top down, just outside of the first cut, completing the cut all the way through and removing the branch.
   
3. As you support the branch, cut just above the branch collar to provide a clean cut near the trunk that won’t tear or break from the weight of the branch.

Safety First

Purdue University Extension lays out safety rules you should follow before trimming bushes, hedges, or shrubs in your landscape:

• Call in a certified arborist for large, unmanageable projects.
  
• Keep your equipment sharp and in good repair.
  
• Use equipment only for the job it was designed to do.
  
• Be aware of electric lines. If a power line is touching a tree limb, call the power company, and stay clear of the tree.
  
• Never climb a tree without a safety rope, even when using a ladder.
  
• Keep fingers clear when using hand clippers.
  
• Wear eye protection while pruning and handling limbs and brush.

Common Mistakes

Correct	Incorrect
● Make a few large cuts instead of many small cuts.	● Don’t “stub” a plant by just lopping it off at the top. That encourages multiple replacement branches to grow.
● Prune just above a healthy bud, with the bud pointing in the direction you want the plant to grow. Cut at a 45-degree angle, with the low point of the cut opposite the bud.	● Don’t cut too far from or too close to the bud you want to encourage.
● Leave a “collar” when cutting off a branch.	● Don’t cut branches flush against the trunk.
● Open up a plant with thinning cuts.	● Don’t cut more than one-third of the plant’s height in any one season.
● Cut at the proper time of year — usually late winter or early spring, though there are exceptions.	● Don’t be afraid to prune — your plant actually needs it to remove dead wood and take on the shape you want.

O’Malley says a common mistake he sees is simply not pruning during the proper pruning period and cutting too much off the plant. Homeowners need to be careful when cutting and make sure there are still some dormant buds below the cut so that the plant can recover.

 “Sometimes when folks cut into old wood, it doesn’t grow back,” he said. “That’s because they cut below those dormant buds, where the new growth would normally pop out after pruning.”

FAQ

What if I Can’t Cut It?

Pruning landscape plants isn’t for the faint of heart, but hopefully, you’re feeling confident. Bushes, hedges, and shrubs don’t yell when you cut them, but they absolutely tell on you when you do it wrong. Still not sure about DIY trimming? Drop the loppers, ditch the snips, and call a professional landscaper in your area. Your plants will reward you with shear happiness.

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