Summer pruning tips for flowering ornamentals, fruit trees

Looking at the tangle of branches and vines in an unpruned garden immediately shows the importance of proper annual pruning. A properly pruned garden has an open, clean, legible and inviting look to it. An unpruned or improperly pruned planting is simply an unreadable hodgepodge and hard to figure out.

It’s like reading these words. The letters are important, but so are the spaces between the words. Ruthless pruning adds airy elbow room that helps you visualize each plant as a separate entity. The empty spaces define the planted areas.

Pruning is a huge subject because of the immense number and kinds of plants. So let’s focus on woody flowering ornamentals and fruit trees.

Woody plants flower and set fruit on new wood or old wood. But there is a fundamental difference that is critically important to know.

New wood is freshly produced during the season of bloom. Think of a modern, repeat-blooming rose bush. You cut it way back when it’s dormant, which encourages lots of new shoots when it wakes up in the spring, and the new wood produces flowers. For old-fashioned roses that only flower in May and June, pruning before flowering would cut off the old wood that carries the buds that will make this year’s flowers, so pruning is done after flowering.

The rule then is to prune old wood bloomers after flowering and new wood bloomers when they’re dormant. (See the list of woody ornamentals that bloom on new or old wood that accompanies this article.)

What about fruit trees?

Fruit trees are pruned to be structurally sound, with strong branches with wide crotches (10 o’clock or 2 o’clock angles) where they emerge from a main trunk and with fruit-bearing branches kept fairly short so fruit doesn’t bend and break the branches. They should also be pruned to a height that’s easy to reach for picking and pruning. And some branches can be thinned out altogether to curb over-production of fruit. While most pruning is done when the plants are dormant, summer pruning helps slow down overly vigorous trees or trees that are growing too tall. This is done right after harvest. Broken branches should be removed immediately.

Apricots have some special needs. Prune your trees in the fall before the onset of winter rains to prevent Eutypa fungus infection of pruning wounds. Remove about 20% of last year’s growth at this time to let light into tree. And never use sulfur on apricots for fungus control. Use dormant oil sprays and antifungal copper sprays instead. Thin fruits to 6 inches apart when they are about 1 inch in diameter.

Peaches and nectarines produce fruit on shoots that were last year’s new wood. That bark will be reddish rather than gray. Prune them back to an outward-facing bud and take off a third to half of their length when the tree is dormant. When the tree wakes up in spring, the remaining branches will produce flowers and then fruit. And while the new growth won’t fruit in this first year, it will become the next year’s fruiting wood (requiring similar heavy pruning every year).

When the peaches or nectarines have set fruit and the babies are about the size of a nickel, go over the trees and prune off fruits so the ones you leave are about 6 to 8 inches apart.

Prune fruit trees first for shape. Prune so the trees have open centers and four or five strong branches around that center. Thin out some of the shoots that bore fruit during the previous growing season back to a main or side branch. Prune back any long, weak growth by half to keep new fruiting wood as close to the main trunk or main branches as possible. Don’t let side branches get so long they become weighed down by fruit and break. Trim them back by at least a third.

Pears don’t need much summer pruning.

Apples are best trained to a central leader, meaning a strong branch that functions as a vertical trunk and from which side branches emerge. This positions the leaves to best intercept sunlight. This is done in the dormant season. Prune out any weak or crossing branches. Some apples, like Red Delicious and Jonagold, bear their fruit on spurs. In early spring, head back side shoots and prune off the tips of branches, which forces the tree to produce more spurs, but nip off spurs closer together than 6 inches.

Some apples, like Rome Beauty, Cortland and Granny Smith, are tip-bearers, but avoid the temptation to cut back the tips or you’ll be pruning off the coming fruit. Prune by cutting back older limbs to the trunk to encourage young, fruitful growth. Thin all apple fruits to 6 to 8 inches apart after the tree sheds some of its excess fruits by itself in June.

As for flowering shrubs and trees, there are two types. The most common type flowers on old wood — that is, wood that grew in the previous season. So, you don’t want to prune off new growth or you’ll be cutting off next year’s flowers. And you don’t want to prune away last year’s growth or you’ll be pruning off this year’s flowers. But woody branches or stems older than two years can be safely pruned to keep the plant open with good sun exposure and airy interiors to keep them dry. You do this pruning after the plant has finished flowering, pruning out 3-year-old (or older) stems and branches.

A smaller set of ornamental shrubs and trees flowers on new wood — on this year’s growth. So, like our rose bush example, prune heavily in the dormant season to encourage new growth. If you miss the early pruning, just wait until after flowering to do your pruning, which should call out new growth during the balance of our long growing year.