Summer pruning is best done in August-September, when the majority of branches have set a terminal bud. Note that when branches are actively growing, their tips feature a vegetative bud that continues to produce leaves and lengthen. This is visible—you see new leaves forming at the tip of a branch.
Summer is an excellent time for restorative pruning. You can correct problems that have resulted from over-pruning or poor pruning. You can also clean up damage from winter and spring storms. Proper pruning will begin to restore most plants' natural shape.
Few plants are pruned this time of year because pruning encourages new growth that does not have time to harden off before winter. Late-season pruning typically does more harm than good.
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.
CORVALLIS, Ore. - You can prune an apple tree any time of the year without hurting it, but late winter, just before spring, is probably best.
It is possible to summer prune after the terminal bud has set to inhibit lateral shoot extension and impending encroachment on neighboring trees or alleyways. This can be done by making a thinning cut back to a weak lateral or fruit spur. This is also the best time to prune if trees are getting too tall.
This is because, while the tree produces fruiting spurs naturally, summer pruning persuades it to produce even more. For various reasons, removing most of a shoot of this year's growth encourages the buds which are left behind to become fruit buds instead of leaf buds.
August is an excellent month for pruning many shrubs and trees in the landscape, just ahead of the fall growth spurt. It's also a perfect time for pruning backyard fruit trees for size control. Removing excess growth now instead of waiting until January will help keep fruit trees smaller.
Now and through the summer months is the time to do any major pruning or cutting back of shrubs and trees. With the fast, summer growth rate upon us the plants will regrow and look beautiful for next fall season.
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 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.
The best season to prune trees is while they are dormant, or generally between November and March. This means waiting for them to lose their foliage and cease growth, but before forming buds. For fruit trees such as the apple tree, prune in late winter.
Wait until just after any fruiting and flowering is complete to cut back. Prune a tree or shrub that produces fruit or flowers too early, and you'll cut off fruit and flowers. Prune the shrub or tree too late, and you may cut off growth that would have produced fruit and flowers next year.
Choose the Right Time
Likewise, prune in the early morning or late afternoon to avoid the newly cut ends of branches becoming scorched by the hot sun. Wait 48 hours after rain to prune, to allow plants to dry out and avoid fungal diseases. When pruning, make cuts just above leaf nodes, or buds.
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. This is the sweet spot for pruning and will help keep everything looking and performing its best.
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.
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).
Did you know that if you prune too late in the season, you stimulate new growth, which will not have time to harden off before the first frost, which will be coming soon to our neck of the woods. This can weaken and damage the plant, so its best to leave the pruning until spring.
Pruning and training
Prune wisteria and climbing shrubs such as Pyracantha after flowering. Hebes and lavenders can be given a light prune after flowering. Rambling roses can be pruned now, once they have finished flowering. Give hedges a final trim over now.
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.
There are some tree species that should be pruned in the summer rather than the winter or spring. These include apricot and cherry trees, as well as their kin. While most fruit trees are traditionally pruned in the dormant season, these guys should wait until summer if possible.
When to Prune an Apple Tree. Pruning is best done in late winter while the tree is dormant, or in the early spring before new growth has begun. If possible, avoid pruning in the summer and fall, as this stimulates new, sensitive growth that may be vulnerable to insect attack and winter damage.