It’s So Important to Prune These 12 Plants in January – Do It Before Winter’s End to Ensure a Healthy Summer Garden

Pruning a plant feels a little like cutting your hair – the process makes things neater and more aesthetically appealing. But unlike haircuts, pruning cannot be performed whenever the urge hits. There are best times to prune, acceptable times to prune, and times that you shouldn’t pick up the pruners for love or money. And, to make matters more complicated, the timing varies dramatically between species.

Why is getting the timing right such a big part of the basics of pruning? While trimming trees and shrubs does tidy up your landscape, it also serves a more important end: preparing the plants for the next period of fruiting, flowering, or growth. Prune a plant at the wrong time and you might eliminate the next crop of blossoms and/or fruits.

January is winter across the Northern Hemisphere, so January plant pruning is dormant pruning. It is the ideal time to prune many deciduous plants – those that do not bloom or bear fruit on new growth.

Plants to Prune in January

Your trees and shrubs are now dormant. Most have lost their leaves, making it easy to see the structure and decide where to make cuts. The ground is likely frozen where you live, so it’s easier to reach tricky spots to make the right cuts.

By pruning trees and shrubs now, you can improve the overall form and control how they shape up and grow come spring. You can easily see branches right now that are dead, dying, or damaged. Fresh wounds on shrubs and trees are less likely to get infected in January, so pruning now is safer for the plants.

It is also important to make sure you have clean, sterilized pruning tools and also that they are nice and sharp. This will reduce injury to the plants and keep from spreading diseases. Our editors love Fiskars bypass pruning shears, available from Amazon, for smaller branches and Fiskars bypass loppers for larger branches.

Trees to Prune in January

January is an ideal time to prune many trees, and these are just a few examples to get you started.

1. Pear Trees

In January, any partridge in your pear tree may well have moved on, just in time to allow for an annual pruning. Pear trees (Pyrus communis) – like most deciduous fruit trees – lose their leaves in fall and go “to sleep” for the winter. This dormant period is the perfect time to get out the pruners.

When trimming your pear tree, remember that they will thrive and produce the most fruit when sunlight and air circulate to the interior of the canopy. Accomplish this by structuring the tree in a pyramid shape, topped by a central leader. Remove all competing leaders and space out lower branches evenly.

2. Oak Trees

Yes, oak trees grow from tiny acorns, and grow, and grow, and grow. They are called “mighty” for good reason – some can grow to the clouds.

With an oak tree (Quercus spp.), you need to be careful to time a pruning appropriately to avoid dreaded oak wilt disease. This disease is spread by sap-feeding beetles that carry diseased spores from infected trees to healthy ones. Oaks bleed sap through branch and trunk wounds, including pruning cuts. Keep beetles out of your oaks by never pruning during the growing (“sappy”) season. Your best bet is to prune your oaks in January.

Oaks can be too tall for do-it-yourself pruning so don’t hesitate to call in an arborist to help. That’s what I do in France every winter. If you want to prune smaller trees yourself, go slowly. Never take out more than one-third of the canopy when you prune, and if you remove entire branches, don’t cut them flush with the trunk. Leave the branch collar intact.

3. Beech Trees

I love all trees, but beech trees (Fagus sylvatica) are especially dear to my heart. Pruning these trees in January is advisable for all the same reasons that apply to oak trees. Like oaks, beeches leak sap when pruned during the growing season, so dormant pruning is the way to go – avoiding setting up your beeches as insect magnets.

Beeches grow upright and elegant in a naturally graceful shape. Simply prune out dead, damaged or diseased branches and remove crossing branches.

For landscape trees, it pays to prune out the lowest limbs during the first few years after transplant to enhance the shape. Though not quite as tall as the tallest oaks, a beech can grow to 60 feet (20m) tall – so keep the arborist’s number handy.

4. Hawthorn Trees

Some trees are classified as “bleeders,” since their sap flows in rivers when pruned in summer. Hawthorn trees (Crataegus monogyna) are bleeders, reason enough to prune them in January. What about the flowers? A winter trim encourages a great floral display in the spring.

Prune hawthorns regularly during their first few years to give them a strong and graceful shape. But as they grow up, cut pruning back to twice a decade. When you prune, leave the branch collar when you remove branches. This is a tree you can shape by making cuts above buds that “point” in the direction you want the branch to develop.

5. Weeping Willow

Willow trees are all fast growing, cheerful trees. But a weeping willow (Salix babylonica) is perhaps the only one of the species that can be called majestic. With beautiful, arching branches and delicate foliage, this tree makes a real statement in your landscape. January pruning of weeping willows is ideal since the tree is dormant and you can get a good view of the branch structure without all the lance-shaped leaves.

Willows all grow fast, which can lead to brittle wood and wear branch attachments. Pruning can help build up the tree’s structure by removing branches that cross, identifying and establishing a central leader, and repairing any winter damage. When it’s pruning time, don’t get carried away. Leave the natural shape of the tree, preserving the weeping form.

6. Crape Myrtle

January is the perfect time for pruning crape myrtle, a large shrub or small tree that flowers in summer and fall. Unfortunately, crape myrtle (Lagerstroemia indica) is a plant that is too often pruned incorrectly. Many people cut them way back, indiscriminately taking out entire branches. The best way to prune crape myrtle is to be more selective.

Thin the shrub or tree by removing crowded, crossed, dead, or damaged branches. Also, remove suckers. If you are training it as a tree, remove lower lateral branches from the main trunk. Finally, trim back branches in the upper canopy that are growing in toward the center.

January pruning is one way to get an early start to the gardening season. Use this time to be thoughtful and selective about how you thin, shape, and maintain your plants for good results come spring.

Shrubs to Prune in January

January is the perfect time to prune some shrubs and bushes, too. However, you shouldn’t prune shrubs that bloom in spring. These should be pruned right after flowering. See which shrubs you should be pruning now.

7. Summer-Blooming Spirea

Spirea shrubs are popular landscaping shrubs that comes in a variety of types and sizes. If you have types that bloom in summer, January is a great time for pruning spirea.

Cut back older, woody stems to make room for new growth. Selectively prune to give the shrub the shape you want. Remove about one-third of the older growth.

8. Roses

Unless you have very cold winters, January is the start of rose pruning season. If you need to wait a little longer because your region is expecting very low temperatures, be sure to prune before very much new growth appears.

Remove any dead, broken, or damaged canes and branches. Remove crossed branches and any that rub against each other. If you still need to remove more to shape the shrub, focus on trimming off weaker or older, woodier growth. You can also remove any rose suckers.

9. Panicle and Smooth Hydrangeas

Pruning panicle hydrangeas is best done in winter or very early spring, but certainly before new growth emerges. They fare well with an aggressive pruning every year. Smooth hydrangeas (Hydrangea arborescens) are also best rejuvenated in the winter.

When pruning hydrangeas, remove one-third to one-half of the growth to reinvigorate a shrub and promote new spring growth.

10. Fall-Fruiting Berries

Dormant pruning is a must for raspberry, blackberry, and currant bushes that fruit in fall. Cut old canes right down to the ground. This will make room for new spring growth. Trim any lateral branches so they are no longer than 12 to 15 inches (30 to 38 cm) to promote larger berry growth later.

11. Arborvitae

Some evergreens, like pines and firs, rarely, if ever, need pruning. One evergreen that can benefit from a dormant trim is arborvitae. The shrubs or trees are desirable for their fast growth and ability to act as a privacy screen. These benefits also mean they need regular trimming for shape and size.

Winter is generally a good time to trim arborvitae, but wait until it is at least two years old and wait a little later in the season if you’re expecting very cold weather. Trim the plants lightly just to maintain size and shape. They don’t do well with hard pruning.

12. Rose of Sharon

Pruning rose of Sharon is best done when the shrub is dormant and when you can clearly see its branches and overall shape. The summer-blooming flowers come from spring buds, so don’t wait too long to prune, or you’ll remove them. Trim out dead, damaged, or diseased branches.

When pruning for size and shape, the approach impacts flowering. If you want fewer, bigger flowers on your rose of Sharon, trim off about one-third of the length of stems. For more but smaller flowers, prune more lightly, taking off only a couple of inches. In general, don’t remove more than one-third of growth.

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