   Pruning Deciduous Fruit Trees - February 22, 2005 Jeff Schalau, County Director, Associate Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Have you pruned your deciduous fruit trees yet? If not, I'll give you some guidelines in writing, then tell you where you can go to attend a live demonstration. Honestly, fruit trees can be pruned any time of year. California orchards have been moving toward summer pruning for several years now. Most people prune in winter to see the branch structure and fruiting wood when the leaves are absent. Winter pruning also tends to invigorate a tree by encouraging vegetative growth. Pruning is not rocket science. However, you need good, clean tools: hand pruners, loppers, and a pruning saw. A pair of gloves is also handy, especially if your tools are as sharp as they should be. It's also a good idea to soak your tools in rubbing alcohol for 10 minutes between trees, especially if you are pruning diseased trees. There are two general strategies that can be used in pruning deciduous fruit trees. Peach, nectarine, plum, sweet cherry, apricot, and fig trees are usually pruned using the "open center" method. The open center method creates a broad vase-shaped canopy increasing light availability and air circulation. This results in healthier foliage and stronger branches which can produce a high quality fruit crop. Increasing air circulation reduces insect and disease potential. The open center method also tends to keep the fruit closer to the ground and easier to harvest. Conversely, apple, pear, sour cherry, and European plum (prune) trees are usually pruned using the "modified central leader method." This method retains the main trunk in the center of the tree as well as some side branches. The side branches are called scaffold branches and should be selected based on their crotch angle and be evenly spaced radiating outward from the main trunk at different heights. The "modified central leader" method results in a sturdy tree that stands up well to harsh weather. However, for backyard fruit production, these trees can also be pruned using an open center method. Pruning cuts also come in two varieties: heading and thinning cuts. A heading cut is typically placed at the tip of a branch to encourage branching below that point. By cutting off the tip, suppressed buds grow out and produce new branches. Heading cuts should only be made if you need to promote branching. Newly planted trees usually need to be "headed" to induce scaffold branching. Thinning cuts remove side branches (not tips) to open up the crown of the tree. In my experience, 90% of pruning is thinning cuts. Once a tree begins to produce fruit, you need to understand exactly where fruit is formed on the tree. Peaches, nectarines, and figs produce fruit on the previous year's wood. Most apple, pears, apricots, plums, and cherries produce fruit on short spurs for a number of years depending on type of fruit. In general, peaches and nectarines need more aggressive yearly pruning than the spur fruiting trees. Ideally, large branches will never have to be pruned because we all prune our trees correctly each year and know exactly what we are doing at all times. So, if one of your neighbors asks you for advice on pruning large branches, do not let them prune it flush to the trunk or main branch. Instead, it should be pruned just beyond the branch collar (swollen area near). The resulting wound has a smaller surface area and will callus and heal over more quickly. By the way, do not use sealants to cover pruning cuts. They are not necessary and can cause decay if applied in thick layers. I could continue with more rules and techniques, but instead here is something to think about: never make a pruning cut without a good reason. Try to understand how trees grow and where they produce fruit. Finally, to learn more, attend one of my free fruit tree pruning workshops. We always have fun and learn together. The next scheduled fruit tree pruning workshop will be held at 10 AM on Saturday February 25 at the the Blazin M Ranch in Cottonwood (just past the entrance to Dead Horse Ranch State Park. The Yavapai County Cooperative Extension web site (ag.arizona.edu/yavapai/) also has detailed information as well as maps to each location. If you can't attend a workshop, North Carolina State University has an excellent web site showing proper pruning techniques at www.ces.ncsu.edu/depts/hort/hil/ag29.html. The University of Arizona Cooperative Extension has information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/. |