Knowing when to trim boxwoods—and which methods and tools to use for the job—is as important for establishing new, young plants as it is for properly maintaining older, larger boxwood bushes. Luckily, with a few snips here and there, it’s easy to spur new growth or simply preserve an existing, desired shape.
Woody perennial shrubs, boxwoods—as well as their cousins the juniper and yew—have served as backbones in the landscape for literally centuries. Hanging onto its broad, glossy leaves year-round, the boxwood is particularly prized for its willingness to be transformed into whimsical topiaries, interesting geometric shapes, living walls, hedges, and more, not to mention its deer resistance.
Do you have to prune boxwoods?
If you want them to thrive, it’s not a matter of if but when to trim boxwoods. Over time, failure to prune boxwood shrubs can result in unwieldy, unchecked growth that can be flattened by snow or look spindly and thin. Furthermore, sunlight and air can’t easily get to the center of the plant and your overgrown shrub may begin to die back. As such, you should make trimming your boxwood shrubs one of your annual gardening tasks.
How to tell when it’s time to prune
Some prominent visual cues can indicate when to trim boxwoods in general. For example, you may begin to notice, in contrast to your shrubs’ old winter color, some tiny green shoots emerging from previously dormant basal buds along your boxwood’s branches. This spring flush of tender growth is one sign that you can lightly shear the plant’s exterior to spur more new leaf development.
Of course, factors like an individual plant’s health, plant age, your area’s growing conditions, and any recent storm damage your plants may have sustained also can affect when to trim boxwoods.
Why knowing when to trim boxwoods matters
When to trim boxwoods matters because, if you heavily prune boxwood bushes too close to the coming winter season, you can stunt their growth or, worse, induce winter die-back. Conversely, if you trim boxwood bushes at the best times, you can encourage new, denser growth exactly where you wish to.
When to trim boxwoods
Thanks to changing weather patterns and shifting first and last frost dates, tying your boxwood pruning chores to specific months like April, May, or early June on your gardening calendar, is no longer ideal. Here’s the real scoop on when to trim boxwoods: as a general rule, the best time of year to trim boxwoods is in very late winter or early spring—just prior to their break from dormancy. So, take a close look at the leader branches inside the middle of your shrubs. When the basal buds along these branches begin to swell in size, the plant’s spring flush of new growth is just around the corner and it’s time to prune.
If you happen to miss that best time to prune, you can still do some trimming and light shaping throughout the spring to roughly mid-summer; however, by late summer or early fall, you should resist the urge to do any heavy cutting because any new growth will not have adequate time to harden off before cold temperatures arrive.
The best tools for pruning boxwoods
- Garden shears—Not to be confused with hand shears or hand pruners (below), garden shears have much larger blades and are best for uniformly snipping through tender stalks and leaves. They are also called hedge clippers.
- Hand pruners—Sometimes also called hand shears, hand pruners are handheld, scissor-like tools best suited for cutting through small branches and dead or damaged woody stems. If you need to extend your reach to prune, opt for long-bladded loppers, a cousin of hand pruners.
- Folding garden saw—Folding garden saws (or pruning saws) are small, foldable, and perfect for sawing through stray branches as well as very thick, woody growth. Although a folding garden saw does require more patience to use than, say, electric hedge clippers, its exceptionally sharp blade can help to reduce the likelihood of torn or split bark.
- Electric hedge clippers—If you have several boxwoods to shear or lightly shape, electric hedge clippers can make quicker work of the job. Still, there are trade-offs. Dull blades can result in damage to the plant. Be sure to not shear boxwoods into a tight little meatball using electric hedge clippers. This is unnatural and can result in unhealthy plants that are more susceptible to pests such as the boxwood leafminer.
Two ways to prune boxwoods
Shearing and thinning are the two main ways to trim boxwoods. In part, which technique you use and when will depend on each boxwood shrub’s condition and your particular goals for it. For instance, if you hope to coax your boxwoods into ornate shapes, you might need to use the shearing method more than once per growing season.
1. Shearing boxwoods
You can encourage vigorous new plant growth by shearing your boxwoods. For this method, you can use garden shears or electric hedge clippers to lightly shape the exterior surface of the entire bush from early to mid-spring. Freshly sheared boxwoods will direct extra energy into developing new leaves and stems. Be sure the blades of your tools are clean and disinfected to prevent the spread of pathogens such as boxwood blight.
2. Thinning/plucking boxwoods
Also known as “selective pruning” or “plucking,” thinning is essential for the long-term health of your boxwoods. It is by far my favorite method of boxwood pruning.
Your objective in thinning is to ensure that some sunlight and air can still reach the center of the shrub. Thinning casually shapes the boxwood and manages its growth and size. The process of thinning involves selectively removing individual branches by hand, cutting them back to just above a pair of side buds (see photo below).
When done properly, thinning does not result in an unnatural shape. Instead, it maintains the natural form of the plant. Soon after pruning, the side buds develop into two new shoots, keeping the plant thick and lush. Use hand shears for the job. Start by removing dead wood and small branches that are otherwise unhealthy. Then move on to pruning the living branches. Clear away all plant debris after pruning.
Watch this video to see how I complete the thinning process on my own boxwoods each season.
Thinning is especially useful for reinvigorating older, overgrown boxwoods. When pruning a really neglected shrub, you may notice bald areas within the center of the bush. While it can take a season or two, most boxwoods will rebound and fill out once again after thinning takes place.
When to trim boxwoods: Bonus tips for success
When pruning, make precise, clean cuts. Pathogens and disease-vector insects can more easily penetrate areas of torn or damaged bark. This, in turn, can potentially result in infection. (For added protection, you can opt for a disease-resistant cultivar like Green Velvet boxwood.)
In early spring, you can also give your boxwoods a boost by applying an all-natural, slow-release fertilizer.
Fit and Trim
Whether you want to grow a formidable hedge maze or go for a more natural look, now you know how and when to trim boxwoods. Remember, it’s best to prune boxwoods just before they come out of dormancy. Depending on your local microclimate and hardiness zone, this might be in very late winter or early spring. The second best time is from spring through mid-summer. Remember, late summer and fall are the worst times to prune boxwoods.
You’ve also learned when to trim boxwoods with just a few light snips of the garden shears and when a more in-depth session is warranted. Both shearing and thinning have their place. Together, these techniques can help you grow, shape, and maintain healthy boxwoods for decades to come.
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