When you look out your window and see tall and overgrown bushes in your yard, does it make you want to close the blinds and forget about them? Don’t worry. All you need is a little bit of knowledge, a few tools, and practice, practice, practice. Even if you’re a novice, this task is well within your reach.
Why should I trim my bushes?
Trimming your bushes is necessary for most ornamental species — eventually. Some require attention more often than others, but trimming is a necessary part of shrub ownership.
Here are a few things trimming will and won’t do:
✓ Help direct the plant’s growth
✓ Improve or maintain health and vitality
✓ Increase flowering or growth
Trimming will not:
✗ Stop a plant from growing to its mature size
✗ Reduce growth (If done correctly, it will increase blooming)
Note: We’ll use the terms trim and prune interchangeably. There may be slight differences, but for our purposes, we’ll use both.
Before you start trimming, consider a few key things:
Knowing your species is a key starting point. It will guide most of your decisions along the way. If you know the variety, even better. If you’re unsure, contact your local Cooperative Extension office. There are also smartphone apps that will help you ID what you see.
- Mature height and shape
How tall and wide does it naturally grow? What is its natural shape?
If you have a plant that reaches 15 feet at maturity, don’t try to keep it at 5 feet. Similarly, if your bush tends to grow in a tall, columnar shape, choose a different species to plant in front of your first-story picture window.
Word to the wise: If, after research and talking with local experts, you realize your bush isn’t a great fit for its current location, it may be time to remove it. Consider relocating the bush to another area of your landscape or donating it to another homeowner.
- Eye protection
- Bypass hand pruning shears
- Pruning saw
Note on tools: The most important way to begin your trimming session is with clean, sharp tools.
Clean: If you’ve used your hand pruners on diseased plants, clean them with rubbing alcohol or a bleach solution before pruning your shrubs.
Sharp: Dull tools are not only frustrating to work with, a cut that leaves the wood torn or ripped can expose the plant to insects and disease. In contrast, a clean cut will heal quickly and properly. If you can’t sharpen them yourself, ask your local small engine repair shop if they provide this service.
To shear or to thin? That is the question. But first, let’s define our terms.
Shear: Cutting with electric or hand-held hedge shears. Cuts are indiscriminate. This method is the most time-efficient but not the best for long-term health.
Thin: Cutting back to the main stem or to a lateral branch or bud. Cuts are not indiscriminate.
The experts agree: thinning is the way to go. To thin a branch, you’ll need to cut it back to a bud or to the main stem. In other words, don’t indiscriminately cut the new growth that shoots out; cut it back to a bud or back to the main stem. If you’re doing final shaping cuts (see flowering bushes section below), cutting at random heights is fine (in moderation).
Remember to follow the rule of one-third: Don’t remove more than one-third of the total amount of wood at any pruning session.
How to thin your bushes: To thin, make an angled cut about one-half inch above a bud if the plant has alternating buds. If a plant has buds directly opposite one another, cut just below the buds at an angle.
Cutting in this way stimulates those buds to put out new growth. If your plants are too leggy, this is especially useful because it helps the shrub to become bushier. As we mentioned above, you also can remove the branch back to the main limb to increase airflow or remove branches you don’t want.
One exception to the rule of one-third is rejuvenation pruning. Rejuvenation pruning is a pruning technique that helps rejuvenate plants that are just starting to become too woody or overgrown. If you want to DIY, do your research before you jump in with your saw in hand.
According to Colorado State, rejuvenation pruning is most successful when at least two-thirds of the branches are alive and have foliage. To do this type of pruning, cut all of the branches back to 6-12 inches above ground level.
It’s important to do rejuvenation pruning in the late dormant season — late winter to early spring, even for bushes that set their blooms last year, like forsythia. Know that you’ll lose blooms for one to three years at least, but you’ll have saved your plant in the long run.
Here are a few species that can handle rejuvenation pruning:
Caveat: Recommendations may vary by climate or variety of plant. Ask your local Cooperative Extension agent for more information before you cut your beloved bush to the ground.
✓ Crape myrtle
These species do not handle rejuvenation pruning:
Sources: Iowa State University, University of Georgia, University of Maryland
Another approach to thinning is called renewal pruning. It’s simple: Remove one-third of the oldest stems each year for three years. (Cut them back to the ground.) After the third year, you’ll have removed all of the old wood. This gets rid of old wood and leaves only fresh, new wood going forward.
Renewal pruning is best used on healthy shrubs to keep them healthy. It’s a good technique to use in the years after you do rejuvenation pruning for overgrown shrubs.
Finally, experts agree that shearing can harm your bushes if you’re not careful. Some say to avoid shearing completely unless you are doing topiary pruning or formal hedges. Others say to use this practice sparingly and don’t advise it more than once per year.
Pro Tip: If you get a lot of snow in the winter, rounded and conical shapes deflect snow, but flat, wide tops collect it. You may still need to tie up certain shrubs or arborvitae, but choosing plants that naturally grow in these shapes will ease this winter chore and reduce the chance for structural damage.
To trim flowering bushes:
Step 1: Remove the three Ds: Damaged, Diseased, or Dead wood
You can do this step any time of year. This applies to deciduous or evergreen shrubs.
How do you know if the wood is dead? If you’re unsure, cut a branch. Is there green along the outer rim? That’s living bark. If the branch is brittle, leafless, and brown along the outer rim, it’s dead. If the whole interior is dead, you may need to replace the bush.
Step 2: Pick the right time of year
Does your bush flower in spring or summer? If it flowers in spring (forsythia, azalea, viburnum), trim the bush right after it blooms. These bushes will bloom on “old wood,” meaning blooms that set last year.
If it flowers in summer (tea olive, beautyberry, crape myrtle), trim it in late winter or early spring before it begins to grow. These bushes flower on “new wood,” or blooms that set this year.
Pruning at the right time of year means you won’t have to worry about cutting off its flowering buds.
Step 3: Take thinning cuts
If the interior branches are alive, take your thinning cuts to encourage new growth. While you’re at it, remove any crossing branches (branches that cross over or rub against another). This helps keep the branch structure open.
Step 4: Final shaping cuts
Once you’ve opened up the plant to light and air, if there are still wispy branches that extend too far, trim those back with your pruners.
Thinning and shaping cuts taken each year will prevent overgrowth in the future.
Many broad-leaved evergreens — like hollies, gardenias, and pyracantha — only require light thinning and shaping each year.
If you prefer small evergreen plants, there are species that also require little if any pruning, including gumpo azaleas and dwarf yaupon holly.
When to prune? Broad-leaved, spring-flowering evergreens should be pruned right after they bloom in the spring, just like spring-flowering deciduous shrubs. Non-flowering evergreens should be thinned, if necessary, in late winter or early spring before they put on new growth but after the last frost.
Some evergreens, such as yews, arborvitae, and hemlocks, also can be pruned in early summer once new growth has begun. (In other words, you can prune some both before and after new spring growth.)
A cut above
Proper pruning may not be rocket science, but it does require patience, time, and a willingness to learn the proper techniques. Once you learn how, pruning shrubs can be an enjoyable part of the time you spend in your garden each year.
Remember to choose the right plant, know how big it will grow, and thin it during the proper growing season each year for the best results. You should have healthier, more vibrant blooms next year.
If your eyes start to cross at the thought of pruning your overgrown, gangly shrubs, contact one of our local lawn care professionals to tame your bushes in no time.
Main Photo Credit: Quinn Dombrowski | Flickr | CC BY-SA 2.0