With fall garden cleanup in full swing, maybe it's all the raking and mulching that has people going bananas. But before you start hacking at your trees and bushes, take a tip from a seasoned gardening expert. "The rules of fall pruning are simple: Prune nothing in the fall!
Pruning can make plants hardier and help them over the winter too. Other plants, however, can't handle fall pruning—such as azalea, viburnum, Loropetalum, and lilac. If you prune a spring-blooming tree or shrub after its flower buds have formed, you'll be lopping away any opportunity for a spring showing.
Don't Prune in Late Summer and Fall
Pruning shrubs in August or early September may encourage a late flush of growth. This new growth may not harden sufficiently before the arrival of cold weather and be susceptible to winter injury.
DON'T prune during fall.
This can weaken and damage the plant—especially if there's an early frost.
Winter is usually the best time.
If you live in an area with distinct winters, the time when shrubs have lost their leaves and become dormant is an excellent time to prune them. Without the leaves, you can easily see the branching structure of the shrub and decide what to cut.
Pruning at this time of year will severely weaken the plants. This is disastrous for the plants and all the hard work you did during the year to make your landscape beautiful.
Late spring, early fall, or winter (when the hedges are fully dormant) are the best times for pruning hedges. Don't prune hedges during very hot, dry weather, and prune well before your first frost date.
Mild fall weather may have you thinking about pruning shrubs and trees. But it's better to wait till late winter, or, at least, after leaves have fallen. Fall isn't the right time to prune trees and shrubs. There are good reasons to wait till late winter or after the plants' leaves have fallen.
Spring flowering shrubs and trees.
Shrubs and trees like lilacs, azaleas, and others will grow best when they are pruned right after they flower in the spring. Avoid pruning them in the winter as it may stunt their growth.
You probably already know just how fast shrubs grow and start to look messy. If you wait too long, your shrubs will start to become an eyesore. Pruning less of the plant but more frequently is by far the best for the overall health of it. We recommend every other month, which comes out to be five times per year.
During excessively cold temperatures
It's minor, but it could impact the look of a plant or create a haven for insects and diseases later. Don't prune when the temperature falls below 25°F.
Common Mistakes
Prune just above a healthy bud, with the bud pointing in the direction you want the plant to grow. Cut at a 45-degree angle, with the low point of the cut opposite the bud. Don't cut too far from or too close to the bud you want to encourage. Leave a “collar” when cutting off a branch.
Overgrown trees can pose a serious risk to your property and your family. Dead or damaged branches can fall and cause damage to your home or car or even injure someone. In addition, overgrown trees can block sunlight and views and can even damage foundations or driveways.
Pruning evergreen bushes is best done in late March or early April before new growth begins. Light pruning can also happen in late June or early July. Avoid pruning evergreen shrubs in the fall, since they are more susceptible to winter injury.
Also, do not cut back hardy perennials like garden mums (Chrysanthemum spp.), anise hyssop (Agastache foeniculum), red-hot poker (Kniphofia uvaria), and Montauk daisy (Nipponanthemum nipponicum). Leave the foliage. It's important to protect the root crowns over winter.
As a general rule, a light summer pruning can be performed on most deciduous trees and shrubs. Heavier pruning should be performed when the tree is dormant, preferably in late winter before active growth begins.
You should trim your hedges at the same time of year you trim most of your trees — late winter to early spring. If your hedge has gotten out of hand, power hedge shears may be the best way to begin. Follow up by hand with freshly sharpened hedge trimming shears to clip away all the stray leaves or branches.
The period between the full and new moon (third and fourth quarters) is best for harvesting, slowing growth, etc.
In temperate regions, most plants go dormant during the winter. This is the time of year when they've halted active growth and have hunkered down for the cold weather. Because of this dormancy, late winter and early spring are typically the best times to make any adjustments to the shapes of many trees and shrubs.
Some perennials, like hostas, peonies and daylilies, need to be pruned in fall to avoid winter damage. Plants like these should be pruned after the first few frosts in late fall or early winter. Other perennials like mums and coneflowers are better off being pruned in spring just before new growth comes in.
Helps Control Disease
Some trees, like oaks, should only be pruned during the dormant season because they are especially susceptible to oak wilt disease, which is known to spread extremely fast in the spring and summer.