Train young fruit trees

As homeowners and gardeners discover the superior taste of homegrown foods, those who have the space often decide to augment their garden vegetable produce with the crops from selected fruit species. With the decision to grow fruit trees also must come the understanding they generally are relatively high-maintenance plants that require a considerable amount of work and the investment in some pesticides to ensure edible fruits. Because the ideal time to plant most fruit trees is the dormant season that stretches from mid-November to early March, it's likely there now are a good many young trees in landscapes and mini-orchards that were planted this past season.

Given the proper care, these young trees can be expected to survive their first summer and will eventually produce their respective fruits as they were intended to do. However, it's no secret we've been experiencing extremely hot weather and near drought conditions lately, so close attention to watering and soil moisture levels throughout the summer is particularly critical.

While your young fruit trees are getting established and beginning to grow in size, they also are developing their own system of branches for bearing and supporting their fruit. Their natural branching is rarely the strongest so far as supporting a big crop of fruit after the tree is of good size, so here is where developing an appropriate system of branches comes into play. Failure to improve branch structure frequently results in severe limb breakage as the tree reaches a mature size and sets a heavy crop of fruit.

In order to minimize limb breakage of mature fruit trees that are bearing a lot of weight, during the first two or three years of growth of the young trees training by selective cutting and using weights or spreader sticks is very desirable. People growing either apples or pears should train their trees to the modified leader system of branching. This system combines a relatively low profile with excellent structural strength. (While it's a bit late for this summer, those contemplating planting either apple or pear trees in the fall should select semi-dwarf trees rather than dwarf or standard trees. There are good reasons why.)

Training to the modified leader system consists of choosing the lowest main (scaffold) branch at a point on the trunk that is either about knee high or waist high, depending on how far from the ground you wish the canopy to start. In landscapes, the waist-high level may not be sufficient to accommodate lawn mowers used to maintain the turf grass, so it's alright to have the bottom branch higher than in an orchard setting. If possible, the lowest branch chosen should face the southwest direction to lessen the chance of winter damage to the trunk. The remainder of the branches should be balanced radially around the trunk with approximately one foot between branches vertically on the trunk. Usually, the top branch will be either the fifth or the seventh from the ground. At this point the main trunk (leader) is cut off at the same angle as the topmost lateral or scaffold branch and that branch assumes the role of developing any additional height. It is thus designated the "modified leader."

When choosing those branches that are destined to become the main scaffolds, make sure each branch makes from a 45 to almost a 90 degree angle with the trunk. Branches with such angles contain more wood and are, therefore, much stronger than narrow angled branches that consist of considerable bark tissue.

Peaches, plums, nectarines, apricots and that general family of fruit trees are, in this region, trained to the open-center or "vase-shaped" system of branching. Ideally, in this system three lateral branches that arise from the trunk at almost the same point are chosen for the scaffold branches and, again, the distance above the ground depends upon the preference of the owner or the situation of the site. Certainly, nothing lower than knee height should be considered. Radial symmetry also should be a part of the decision on what branches to keep and what not to keep.

As a beginning, leave the entire canopy for a while. After several branches have developed along the trunk, carefully examine some of the lower branches of the canopy and if you find three strong lateral branches growing from the trunk at about the same level, mark these for your future scaffolds. Once these three have developed acceptable angles with the trunk (45 degrees or slightly more), cut the main trunk just above where they join it.

The next step is to nip the ends of these three scaffolds when they reach a length of 18 inches or there about. Normally, this causes them to form two branches at that point. Later, these six smaller branches (two at the end of each main scaffold) should be nipped when they reach a length of 18 inches. Repeat this process once or maybe twice more to form the complete system of branching for the mature trees. Not uncommonly, the completion of training a tree spills over into the second growing season, so don't be concerned if summer is over before you finish the job. In fact, it's best not to do any pruning and training beyond the middle of August as you can force growth that doesn't have time to harden off before winter arrives. And tender tissues are subject to cold injury or even will be killed if winter temperatures are low and last long enough.

Improving branch structure on any kind of young tree is a good practice and often can materially strengthen the canopy, possibly avoiding major damage from wind and ice storms as the tree reaches maturity. And when trees are young, hand pruners, lopping shears and a small pruning saw are all that's needed to do the required "surgery."

Joe W. White is a retired Extension horticulturist with the LSU Agricultural Center. Write to him in care of The Times, P.O. Box 30222, Shreveport, LA 71130-0222, or e-mail to jo2bar@sport.rr.com.