Winter pruning is analogous to pouring the foundation and framing the house: it creates the tree's structure, form, and extent. Summer pruning is all about “finish work”: trim, tile, cabinetry, etc. It refines form and keeps the interior of the tree open to sunlight, which is vital to fruit production.
Summer pruning involves cutting back new shoots to allow light to reach the fruit. New shoots are stiff and woody along their bottom third, with dark green leaves and a cluster of leaves at the base.
Late summer or early fall pruning causes vigorous re-growth of tissue, which in some cases may not harden off by the time winter arrives, leading to possible cold damage to the new growth.
Winter pruning takes place in winter, when plants are dormant. Advertisement. The aim of winter pruning is to encourage vigour so that fruit trees are productive and shrubs don't outgrow their space. This is the time to prune your roses, cut back clematis and reshape fruit bushes and trees.
In fact, it is better to prune a little at a time than to make drastic cuts. For plants that shed their leaves (deciduous plants), the best time for winter pruning is from the beginning of November to the end of February. To prune evergreens you can start later, from mid-December, and continue until February.
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.
Summer pruning is best done in August-September, when the majority of branches have set a terminal bud.
For most trees, the best time for major pruning is late winter to early spring because wounds close faster. Pruning in late summer and early fall may also stimulate new growth, which has little time to harden before cold weather comes.
Prune most broadleaf evergreens now: abelia, boxwood, cleyera, elaeagnus, nandina, privet, and holly. Wait until after flowering for spring bloomers. Viburnums (both evergreen and deciduous) can be cut back hard to reduce size, but you will sacrifice flowers for the season.
Maples. Along with birches, elms, and other so-called "bleeder" trees, pruning maples in winter can lead to a great deal of sap. Wait until summer to avoid a possible mess.
Never shear a shrub in fall (or ever, actually, but that's another article) and leave major pruning or renovation for late winter/early spring, or immediately after bloom for spring-flowering shrubs.
Any gardening expert will tell you, (contrary to what you may believe) that pruning encourages new growth just when the plant is trying to go dormant and new growth doesn't have enough time to harden before the first frost and freezing temperatures hit. Pruning at this time of year will severely weaken the plants.
Surely there's one chore you can tick off your endless outdoor to-do list—and maybe even get a jump on for spring. The rule on fall pruning is, generally speaking, don't prune in fall. But there are a few trimming tasks you can take on with confidence, provided you approach the job with self-control and a plan.
In pruning, there are three primary types of pruning cuts, thinning cuts, reduction cuts, and heading cuts, each giving different results in growth and appearance.
The 1/3 rule involves cutting about 1/3 of wood during any pruning activity. This moderate pruning practice is a balanced approach to thinning out shrubs to stimulate new growth. The plant loses a good amount of stems, usually on the top section, allowing more light and air to enter the inside of the plant.
The two basic types of pruning cuts are heading and thinning. Thinning cuts are the least invigorating type of cut and are the most effective pruning cut for maintaining woody plants in their natural form. Pruning, particularly heading cuts, stimulates regrowth very close to the pruning cut.
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.
It's common to think that everything should be chopped down to the ground in the fall, but some perennials actually need their foliage to protect new shoots through the winter. Other varieties offer up important habitat for local wildlife and some perennials provide height and interest through the winter months.
Generally, the best time to prune or trim trees and shrubs is during the winter months. From November through March, most trees are dormant which makes it the ideal time for the following reasons: Trees are less susceptible to insects or disease.
Don't shear the branches of spring flowering shrubs (Forsythia, Lilac, New Mexico Privet, Spirea, Flowering Quince, and others). These shrubs produce flowers on last year's wood, so removing old growth will reduce or prevent flowering. These plants should be pruned immediately after they are done blooming.
Don't prune too late in northern regions.
In areas with cold winters, avoid pruning after the middle of August. If you prune too late, you may stimulate new growth that would not have time to grow thick, protective bark before the killing frosts of winter.
Summer pruning plays an important role in the removal of dead, damaged, and diseased tree limbs. Any limb that has the potential to cause damage or stress to your tree should be removed.
If it's raining – don't prune! Wait until you have a few days of dry weather. Rain can spread disease. Get the right tools.
Perennials to prune in early summer: joe-pye weed (Eutrochium), tall coneflower (Rudbeckia 'Herbstonne'), bee balm (Monarda), catmint (Nepeta), yarrow (Achillea), balloon flower (Platycodon), Culver's root (Veronicastrum), Veronica and garden phlox (Phlox paniculata).