Summer pruning for more apples and pears.
MOST GARDENERS associate pruning apple and pear trees with the winter dormant season, when it's important to work on a tree's shape. But summer pruning has many benefits, too, including a significant boost to fruit production.
According to Mark Sammons of UC Santa Cruz's Agroecology Program, summer pruning is actually a very simple technique that's been used for years on espaliers and other intensively trained trees typical of some densely planted orchards. For home gardeners with one or several apple or pear trees, the method is easy to master and quick to perform.
WHAT ARE THE BENEFITS?
The biggest benefit of summer pruning is a greater quantity of fruit relative to the size of the tree. Pruned trees channel more nutrients into fruit production, rather than excessive foliage. The fruit also grows larger, and blushed or red types develop better color.
Enhanced disease resistance is another benefit. Pruning opens up the tree and improves air circulation, which helps prevent diseases.
The technique also has a dwarfing effect. The 'Mutsu' on a dwarfing rootstock (MM106) shown here has been kept at 8 feet, rather than growing the typical 18 to 25 feet. This can be a big plus for gardeners with little space. It also means fruit is easier to harvest.
WHICH TREES CAN BE PRUNED? WHEN?
Any healthy apple or pear tree older than three years (it should have developed its main structure) that's growing on a dwarfing rootstock can benefit from summer pruning. It's not suitable for standard-size trees, which are too vigorous. In hot inland areas, the technique should be modified to remove less foliage, or the fruit will sunburn.
The best time to prune is when new growth is about pencil-thick; the stem tip should be succulent and the base starting to turn woody. In Southern California, this is normally about the beginning of June. In the Santa Clara Valley, south of San Francisco, it's usually about the third week of June. In cool, northern coastal areas, trees may not be ready for pruning until early August.
Pruning is confined to shoots on the lateral branches; branches that form the main structure of the tree are left unpruned. Also, leave the two shoots closest to the ends of the branches unpruned until the tree has reached the size you want.
When conditions are right, all of the dormant buds in the remaining leaf axils (where a leaf joins the stem) of the pruned shoots will form fruit in the following year.
SIMPLE STEPS FOR BOOSTING APPLE OR PEAR PRODUCTION
TO BEGIN PRUNING, SELECT a branch and find the third shoot from the end (start at the top if your tree is already the size you want it).
Prune the stem back to just outside the third leaf. If the stem is somewhat thinner than a pencil (under 1/2 inch), prune just above the second leaf. Prune weak and thin lateral shoots above the first leaf. Work down the branch, pruning the remaining laterals, then work your way around the tree, pruning the other branches the same way.
In areas with long growing seasons where trees are irrigated, buds may grow into new shoots after pruning. If this happens, repeat the pruning operation a second time during or right after harvest (don't do this second pruning in colder climates if new shoots appear).