Drop Those Pruners! Why Gardeners Say You Should Wait to Trim Your Plants

Pruning is essential for almost all types of plants that live longer than one season from houseplants to landscape shrubs to trees. As with most activities in our lives, timing is everything. Pruning too soon can leave plants vulnerable to insects or disease and pruning too late can reduce the number of showy blossoms or fruit harvest.

While some plants should be pruned while they are in a state of dormancy (usually in January or February), that’s not a hard and fast rule. The best practices for when to prune depends on the plant species and your hardiness zone.

We talked to plant experts about the best time to prune plants. So, before you pick up your gardening shears or loppers, pay attention to their sage advice.

When to Prune Your Plants

Flowering Shrubs

Bodie Pennisi, horticulturist at the University of Georgia’s Extension office, recommends this guideline: plants that flower before May should only be pruned right after they bloom.

“Flowering shrubs form flower buds at different times of year, so pruning times must be adjusted accordingly,” says horticulturist Bodie Pennisi. “Spring-flowering plants such as azalea and rhododendron, dogwood, forsythia, and redbud, set flower buds in the fall, so pruning during winter months eliminates or decreases spring flowers.”

Pennisi also recommends pruning summer-flowering shrubs in the winter.

“Plants like crape myrtles and abelias that typically flower after May form flower buds on new growth and can be pruned during the winter with no effect on their flowering,” she adds.

There are exceptions, of course. Oakleaf hydrangea, a summer-flowering shrub, forms flower buds the previous season and should only be pruned right after flowering according to Pennisi. Because there are so many different types of roses, follow the temperatures in your growing zone and prune them when the buds begin to swell. 

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Deciduous Trees

Edward Gilman, author of “An Illustrated Guide to Pruning”, recommends pruning deciduous trees just before growth resumes in early spring.

“Pruning when a tree is dormant minimizes the risk of pest problems associated with wounds and allows the tree to take advantage of the full growing season to begin closing and compartmentalizing wounds,” Gilman says.

Evergreen Trees and Shrubs

Broadleaf evergreen trees, like magnolias and hollies, usually require little or no pruning. Needle evergreens are best pruned in early spring before the heat of summer.

If you must prune broadleaf shrubs like boxwoods, evergreen shrubs like boxwoods, gardenia, viburnum, and barberry should be pruned in spring after the first new growth appears to help maintain their shape. Pruning should include thinning branches rather than just shearing off new growth tips.

Plants That Should Be Pruned in Winter

Pennisi recommends later-winter pruning for ornamental flowers that aren’t being grown for their blooms.

“In areas with mild winters, do not prune too early in the winter because it may encourage tender new growth that is not sufficiently hardened if temperatures plunge.”

Here is a list of plants that can be pruned in January and February in most hardiness zones:

• Beautyberry
• Camellia
• Glossy Abelia
• Japanese Spirea
• Mimosa
• Rose-of-Sharon (Althea)
• Sourwood
• Anthony Waterer Spirea
• Sweetshrub
• Fruit trees

What You Should Do For Your Plants in January and February

If you’re itching to get your garden ready for spring, leave the pruning shears in the tool shed and concentrate on these gardening projects.

• Focus on houseplants. If the weather doesn’t cooperate for outdoor activities, focus on the care of your houseplants. Check for insect problems like spider mites and mealybugs. Check humidity levels in your home, keep plants away from drafts and drying heat vents, rotate plants so they receive the proper amount of light.
• Start seeds indoors. Depending on your hardiness zone, January and February may be the perfect time to start vegetable and flower seeds indoors. Check the germination time on the seed packet so you will have seedlings ready to harden off when the outdoor temperatures are mild.
• Monitor outdoor temperatures. In some areas, the threat of extremely cold temperatures are gone by mid-February. You can begin sowing cool-season crops, uncovering plants with winter protection wraps, and clearing away debris like fallen limbs and leaves.