Cornell Orchards

Basic Fruit Tree Pruning Info Pruning is probably the most important task in the orchard and often the most misunderstood. Cut too much and you get several feet of growth each year and little fruit to show for your efforts. Prune too little or not at all and you can end up with stunted trees that produce small fruit and inconsistent crops. By understanding a few of the basic concepts of fruit tree growth, you can understand why trees perform the way they do. Apples/pears/cherries/plums produce their best fruit on 2-3 year old wood. Peaches put their fruit on last year's vegetative growth. The reason for annual pruning is to keep the appropriate age wood in the tree, i.e. lots of one-year wood in peaches and 2-3-year wood in the others. At Cornell Orchards we have 70 year-old trees that are still very productive because our annual pruning promotes the right amount of new growth. Plant hormones are produced in the bud at the tip of each branch. These hormones suppress the growth of buds below the tip and their affects can be manipulated by pruning and branch-bending. The influence of these hormones is greatest on vertical shoots and least on flat limbs. Spreading branches down near horizontal promotes new shoot development and initiates fruit buds. Most fruit trees are grafted or "cloned" to keep the exact traits of a variety. If trees are grown from seeds, their parentage can't be guaranteed, since most fruit is insect pollinated. However, grafting produces trees which are exactly like their parents. Nursery trees are produced by grafting a known variety such as Cortland apple onto a rootstock. Rootstocks are nothing more than fruit trees that have been developed for certain characteristics such as dwarfing, resistance to root disease/insect, earliness of fruiting, etc. Once the grafting of the desired variety onto the rootstock is complete, the rootstock is cut off just above the ground but still provides the root system for the new trees. If you purchase a tree grafted onto a 'dwarf' rootstock, the overall tree at maturity will be a quarter of the size of a full size or 'standard' sized tree. This can be a real advantage in many ways - easy picking, pruning, spraying, faster fruit production (2-3 years instead of 5-6), and more production from a small space. However, deer love to munch on these low trees. Support with stakes is a must and dwarf trees are more sensitive to drought and other stresses. Knowing what overall size the trees are supposed to be (what rootstock) will help to determine how to prune them. Severe pruning of young trees will slow their fruit development. Light pruning coupled with branch spreading will produce fruit in 2-3 years. Heavy pruning will delay fruiting for several years. Pruning Young Trees: Concentrate on developing 3-5 main branches starting at 24" above the ground. These should be well spaced around the trunk to fill all sides of the tree. Spread these to at least a 45° angle. This will promote development of side branches and fruiting wood. Wooden or plastic sticks, string, weights or whatever can be used for this. Leave these spreaders in for one growing season. Strive for seasonal growth to be around 18-30" for the first three years. Make sure the largest diameter branches are in the lower parts of the tree. This will produce the desired Christmas tree shape. Big, strong branches which compete with the main leader should be removed completely. · Wait to prune young trees until late March. This should get them past the worst of the winter cold. · When you get the first fruit, thin it out judiciously to avoid overloading the trees. For apples, pears, and peaches, thin to one fruit every six inches. Pruning Mature Trees: First examine the tree for past growth. Ten inches of annual extension growth is ideal (measure from the tip of the main branches down to where the first "ring" which encircles the branch). Also, think about the crop from last year. Prune harder when following a heavy crop and prune lighter after a small or non-existent crop. Strive to develop a Christmas Tree shape. Remove limbs in the top of the tree completely that are more than half the diameter of the main trunk or leader. Do little or no heading cuts (cuts that remove a portion of a limb by 'stubbing'). These cuts usually promote a lot of regrowth right near the stub and this shades the limbs below. Cut out dead and diseased wood completely. If two limbs compete for the same space, remove one completely, don't stub them both. Do not stub-off upright vigorous branches. Either leave them alone or remove completely. Prune drooping brances back to an upward pointing branch, preferably at a 45° above horizontal. Try not to prune more than 25% of the total volume of branches at one time. Regrowth can often be tremendous and difficult to control. The exception to this is on trees that are stunted with little or no new growth. In these cases, severe pruning can give trees a needed "wake-up" call. It is best to prune moderately every year than severely every few years. Try to wrap up your pruning before growth starts.

Rick Reisinger, Cornell Orchards Manager, organized this information for a Cornell Cooperative Extension course that he teaches on getting started with a backyard orchard and an introduction to pruning. To find out more about this course, please contact Rick at 255-4542 or RDR3@cornell.edu