When to Prune Trees and Shrubs

Why Prune Shrubs and Trees?

Most shrubs and trees do not have to be pruned, but they can benefit from pruning to improve their shape and structure. Keep in mind that pruning isn't bad for trees; rather, it keeps the plant stronger with less risk of disease and pests. A good hair cut can make a tree look better, too!

1. Plant health is the primary reason for pruning. Look for the 4 "Ds"—dead, dying, diseased, or damaged branches—these should be removed. Also look for spindly or weak growth, as well as any branches that are crossed or rubbing.
2. Safety is another important issue. Low hanging branches can be eye-pokers and get in the way when you are trying to work or play around a shade tree. Pruning these branches is called "limbing up." Not only does it encourage top growth, it also makes room for you to safely enjoy the area under the tree. If your trees have any weak, dangling branches that could break off unexpectedly, they pose a danger to people, cars, buildings, and valuable plants underneath. If these branches are high up in the tree, very large, or near power lines, it is best to call in a professional tree trimming company.
3. Pruning can make plants hardier and help them overwinter too.
4. Often, a plant needs pruning to control its size. Overgrown shrubs can be brought back to scale, large shade trees can be reduced enough to cast less of a shadow, and fruit trees can be kept to a reasonable size, making care and harvesting easier. Hedges can be maintained at the desired size and shape. Water sprouts (small, spindly branches) that grow straight up from the limbs of a fruit tree will not bear fruit and should be clipped off as they develop.
5. For some plants, pruning encourages flowers and makes room for new growth. Of course, the time of bloom is critical to know WHEN to prune. In general, the best time to prune a flowering tree, shrub, or vine is after it finishes blooming so you don't cut of its flowers for the season!

When to Prune Trees and Shrubs

When to prune trees and shrubs is a hot topic, and it's no question that spring is the ideal time to inspect your trees and shrubs for winter damage. It is much easier to see the structure of deciduous plants without their leaves, so pruning can be accomplished quickly and easily. Most trees are still in a state of dormancy and will bleed less sap, and insects and diseases are less active.

The correct time to perform this type of pruning depends on when the plant blooms.

Prune Spring-Flowering Trees and Shrubs After Bloom

Prune spring-flowering shrubs and trees right after they bloom in the spring. Do NOT prune in fall or winter.

These plants develop their buds on old wood—branches that grew last year. By fall, they've already formed their flower buds; if you cut off the flower buds, you won't get any spring blooms. Pruning after they bloom gives new growth plenty of time to ripen before winter and bear maximum flowers next spring.

Shrubs that are spring bloomers include:

• Forsythia
• Lilac
• Star magnolia
• Mock orange
• Azalea
• Camellias
• Oakleaf hydrangea and and mophead type hydrangeas (Hydrangea macrophylla)
• Rhododendron
• Mountain laurel
• Loropetalum
• Dogwood
• Flowering cherry, peach, plum, pear, crabapple
• Quince
• Andromeda
• Spirea
• Viburnum
• Maples, birches, dogwoods, walnuts, and elm trees (wait until summer)

If you wait until after they bloom, you can deadhead and prune at the same time. This will encourage lots of new growth and give you more flowers next year.

Mature shrubs should be pruned hard, cutting back most of the flowering stems to a healthy new shoot and taking the oldest growth (but no more than 1/3 of the oldest stems) right back to the base each year so it is completely renewed every few years. A very overgrown shrub should be renewed in this gradual manner too. Young shrubs should have the weakest growth cut back with the remainder pruned just to shape and size. Weed, water and mulch with compost after pruning is done.

Prune Summer-Flowering Plants in Winter

Prune summer-flowering woody plants while dormant in late winter (or early spring) to encourage more new wood to form. Pruning in the fall stimulates new growth just when the plants are trying to go dormant; this weakens plants. These plants form flower buds on new growth next season, not the old growth of last year. 

Pruning summer blooming shrubs in late winter can encourage lots of new growth and flowers for the coming season. 

• Beauty berries
• Hydrangea paniculata ('Annabelle', 'Limelight', and peegee type hydrangea)
• Rose of Sharon, Hibiscus
• Gardenia
• Clethra
• Buddleja set their buds on new wood.
• Angel's trumpet
• Crepe myrtle
• Roses
• Abelia
• Fruit trees: Bradford and Callery pears, crabapples, cherries, plums
• Poplar, spruce, junipers, sumacs (prune in late winter)

Note that when you prune hydrangea depends on the variety. See how to prune hydrangea varieties.

Non-Flowering Trees and Shrubs

• Late winter during dormancy is also the right time to prune any nonblooming trees and shrubs as well as conifers. 
• However, you can lightly shape hedges and conifers any time or the year. In addition, it's fine to trim back small-size twigs and branches any time of year. 
• Of course, always remove dead or diseased branches as soon as you're able to do so. Don't leave a tree weakened by dead and dying branches.

5 Tips on How to Prune

The art of pruning is a skill that you can develop over time. Don't be afraid to experiment and learn as you go, and don't hesitate to consult a good book on the subject or check with your county extension office for information on pruning specific plants. By knowing your plant, its purpose, and especially when it blooms, you will be able to prune it correctly.

Be careful not to over-prune. As stated, pruning isn't critical but it has its benefits for the plant's health and better bloom (and for wildlife). Keep in mind that not all shrubs need to be pruned on a regular basis. For example, shrubs that have a naturally compact habit only need pruning to remove an occasional stray shoot or broken branch.

1. When pruning shrubs, first remove any dead or dying branches. Cut between the diseased spot and the body of the plant. Then remove the oldest, tallest growth first and then take out weak or spindly stems. Prune branches which rub or cross each other or branches that are growing vertically (cutting the smaller branch). You can also take off really low branches.
2. Prune back to the main stem, cutting the branch as close to the source. Don't let stubs stick out; this invites disease.
3. Cut at the same angle as the branch collar—the furrow of bark where branch and trunk meet. If you’ve done it right, a circle of healthy callus will eventually swell around the spot.
4. Never prune if it's damp or wet out; this spreads a lot of diseases. Wait for a dry day.
5. Always clean your tools with hot, soapy water to avoid spreading disease. If you cut off a diseases branch, clean before moving onto the next tree. You can also disinfect the tools by using just a teaspoon or two of bleach in warm water.

To learn more about how to prune, see our Pruning Pointers for Trees and Shrubs and also Spring Pruning Guide for Trees and Shrubs.