When to Prune Shrubs
When it comes to a perfectly manicured yard, timing is everything
Highlights
Prune flowering shrubs after they flower but before new buds form.
Prune evergreen shrubs in early to late spring.
Most shrubs can handle being pruned up to one third of their height.
Pruning shrubs at the right time will keep them healthy and lush. But not all plants are the same, so knowing when to prune shrubs can be a challenge. Luckily, there are some simple ways to determine the right time to trim back almost every type of bush or shrub you could have in your garden. Whether you decide to prune your shrubs yourself or hire a local tree pruning service to help you with the task, here are some helpful tips to keep your pruning schedule on track.
Flowering Shrubs
The best time to prune flowering shrubs is right after they flower but before new buds form. To make sure you get good blooms the following season and that the plants grow healthy foliage in the spring, timing for trimming is important. Here are some guidelines for pruning flowering shrubs.
Early Spring Flowering Shrubs
If you have a shrub that blooms in early spring, such as an azalea, forsythia, or lilac, trimming it right after it has flowered is best. Although most flowering species form buds in the springtime, early spring flowering plants form buds in summer that overwinter on the plant. Trimming these types of flowering shrubs in late fall or winter will kill next year’s crop of flowers and can damage the plant’s ability to grow healthy leaves.
Late Spring and Summer Flowering Shrubs
You can usually prune shrubs that flower in late spring and summer, like roses, oleander, and mock orange, during late winter when the plants are still dormant and before they form buds. Make sure to check the branches of your shrub for buds before you trim. Although you won’t be cutting off new flower buds if you trim these shrubs during the summer, you might be stifling their growth. Pruning during the hottest stretch of the summer, which is another time when the plants are often dormant, is also an option for late spring and summer flowering shrubs. Just do so with care so you don’t remove too much of the foliage the plant needs for photosynthesis.
Late Summer and Autumn Flowering Shrubs
Flowering shrubs that bloom in late summer and autumn, like rose of sharon, butterfly bush, and daphne, should be pruned in late winter or early spring. Trimming them before they form buds will help them form healthy foliage and flower prolifically all season long. These bushes shouldn’t be pruned right after they bloom because they are still active into the beginning of the winter. Taking advantage of their dormant season from late winter into early spring will protect their blooms and help them to produce fresh growth during their active season in summer and fall.
Evergreen Shrubs
Evergreen shrubs are divided into the three major categories below, and although they might appear similar, they have different needs when it comes to pruning. Here’s how to handle pruning the different types of evergreen shrubs and when to do so for the best results.
Juniper Shrubs
Juniper varieties of evergreens should be trimmed in early spring before they sprout any new growth. At this time of year, you will be able to shape them before the new growth comes in, keeping newer sprigs healthy while making the shrubs look full and well shaped. You can technically prune them at any time when the weather will be above freezing, but trimming them before new growth comes in will make them grow more evenly. You should never prune juniper shrubs when it’s below freezing, because this can seriously damage the branches.
Arborvitae Shrubs
You should trim arborvitae shrubs in early spring, once the risk of frost has passed. You can also choose to do a second pruning of your arborvitae in fall, before freezing temperatures hit, in order to keep them well-shaped and thick. Doing any trimming of your arborvitae during freezing temperatures can damage the new growth on the branches that hasn’t had the chance to develop its thicker bark for winter.
Pine Shrubs
Pine shrubs can only be trimmed once new growth has begun. This usually occurs in early to late spring, and you will be able to see it because it will be a lighter shade of green than the rest of the needles. These growth shoots, sometimes referred to as candles, can be trimmed by one third to one half once they appear in order to keep the shrub evenly shaped. Pine trees can’t produce new growth from the woody stems once they have formed bark, so to avoid damage, you should never prune into the existing branches of the tree.
Topiaries and Formal Hedges
If you plan to trim with a hedge trimmer for shaped shrubs, you should wait until you notice new growth on your shrubs in spring. Since these types of shrubs are at their most active in spring, it’s a good time for them to recover from a comprehensive trimming. For topiaries that require a lot of shaping, you can trim them whenever necessary through early fall. But don’t prune them in late fall or winter, because you’ll stimulate new growth on the plant and won’t leave it enough time to grow a protective outer bark before temperatures get below freezing.
Frequently Asked Questions
Some people like to prune shrubs for aesthetics. Keeping the foliage full and well shaped is important for looks. But domesticated shrubs also need to be pruned to get rid of old growth and to stimulate new growth to form. In the wild (and sometimes in domestic gardens as well), plants are pruned by wildlife like deer and rabbits. But if your plants don’t routinely get nibbled on, you can artificially reproduce this effect by trimming your shrubs to keep them healthy.
In general, you can prune up to one third of the height of most shrubs without damaging them. There are a few exceptions to this rule: Pine shrubs, for example, can’t be trimmed below the point of new growth without damaging them.
Pruning when it’s too cold can damage new growth, since it doesn’t have a protective skin to insulate it from the cold. Most plants are okay to prune as soon as the risk of freezing has passed, although early spring flowering plants can’t be trimmed until after they flower to avoid cutting off buds that have overwintered on the plant.
Mid autumn is the latest that you should leave pruning for the year. This is because pruning stimulates new growth, and that new growth needs enough time to grow bark to protect itself from freezing temperatures. If you live in a more temperate climate, check your local weather forecast for the first predicted frost and prune at least three weeks before that date.