By Mary Helen Ferguson, Extension Agent, Horticulture
Fruit tree training and pruning is a topic of great interest and considerable uncertainty for many. The fact is that even two knowledgeable people may shape a fruit tree in different ways. While there is room for variation in how people train and prune, there are principles to remember and important differences between, e.g., training and pruning apple and peach trees.
When NCSU-based Cooperative Extension tree fruits specialist Dr. Mike Parker gives a pruning demonstration, he makes an analogy between raising kids and growing fruit trees: You need to start them out in the right direction, rather than wait until they’re several years old and have become unmanageable brats (in the case of kids) or unkempt messes (in the case of fruit trees) to start trying to correct behavior (kids) or shape (trees). This starting them out in the right direction is called “training.” The corrective action taken later, on trees, is called “pruning.”
One of the main objectives of training, which should begin in the year of planting, is to develop a good limb structure for future fruit production. The central leader or modified central leader training system is common for apples, pears, persimmons, and plums. For peaches and nectarines, the open vase system is recommended. Figs are grown as multi-trunked trees, or bushes, in our area.
From my perspective, the ultimate purpose of pruning is to produce quality fruit that can be picked with reasonable ease. A major part of pruning is opening up the tree to allow more light penetration and air movement. A plant with too many leaves may cast too much shade on potential fruiting sites and the leaves that support fruit maturation.
Having a canopy (composed of leafy branches) that is too thick can also mean that air and pesticide sprays won’t move through the tree well enough. Air needs to be able to move through the plant so that water will evaporate quickly, since diseases tend to develop when leaves stay wet. Similarly, for plants (e.g., peaches) that require pesticide use for high quality fruit production in our climate, sprays need to be able to get into the canopy of the plant.
Steps involved in opening up the tree canopy include removing selected branches so that the ones that remain are spaced far enough from one another and taking out shoots that are growing straight up from, or directly under, other limbs.
In addition to opening up the canopy, another part of pruning is removing any dead or diseased wood.
Also, I think most people would like to be able to pick fruit conveniently. Some people may not mind climbing a ladder, while others would rather just pick from the ground. Pruning can be used to help keep fruit production on some plants at a convenient height for picking. However, trying to keep, e.g., a semi-dwarf or full-sized apple tree short may just result in a lot of vegetative (leaf/shoot) growth and little fruit production.
Late winter and very early spring (shortly before trees break bud and start growing) are good times to prune fruiting plants. It’s a good idea to do some summer pruning (removal of upright growth, largely), as well, on apples and peaches.
I’ve touched on some of the basic principles of tree fruit training and pruning, but there is much more to know. For example, I mentioned at the beginning of the article that there were differences in training and pruning apple and peach trees. One difference is that apples bear fruit at the tips of branches or spurs, while peaches produce fruit along the sides of year-old shoots. Thus, while cutting peach shoots back by about one-third of their length during the dormant season is fine, snipping off the tips on branches of apple trees will often remove fruit buds.
For more information, check out Training and Pruning Fruit Trees in North Carolina (http://cals.ncsu.edu/hort_sci/extension/documents/ag-69.pdf) or give me a call (336-318-6000).