LSU AgCenter's Weekly Message

Training and Other Care of Apple Trees

In the last article, which addressed apple variety selection and planting, I promised that the next one would address training and care.

Apple trees are usually trained in the central leader form. If there are multiple upright-growing shoots at the top of the tree at the time of planting, remove all but one. If there are outward-growing branches below the leader, you can leave one to several of these spread out around the trunk to be the first whorl of “scaffold” branches. These branches should have wide angles with the trunk instead of growing upright. You’ll likely need to spread these limbs, so that they’re slightly above horizontal. (Don’t spread them so much that they dip below horizontal.) A variety of methods can be used to do this. Toothpicks (for very young shoots), clothes pins, wooden spreaders, or homemade weights can be used. If you use string or rope, be sure to remove it before it girdles the limb.

If no good candidates for scaffold branches are present, newly planted apple trees can be cut off at approximately 2.5 to 3 feet from the ground during the dormant season, shortly before growth begins, to encourage branching. During the growing season, several shoots will likely arise from just below the cut, and several more will grow within the space 4 to 12 inches below the cut. You can then select one of the upright growing shoots arising just below the cut to be your new leader and up to four of the lower, outward growing shoots to train as the first whorl of scaffold branches.

A process of cutting the central leader approximately 2 to 2.5 feet above the highest scaffold limb during the dormant season to encourage branching and then selecting one new leader and one to several scaffold branches during the growing season can be repeated for several years. When the tree gets so tall that pruning is impractical, you can cut the central leader at about 10 feet tall, just above where a lateral branch emerges.

Wait until new growth begins on recently planted trees to apply any nitrogen-containing fertilizer. In the first few years, you can use the equivalent of 1 ounce nitrogen per year age per tree. Spread out fertilizer under the drip line of the tree, placing it no closer than about 10 inches from the trunk. Examples of fertilizer rates that supply 1 ounce of nitrogen include 0.5 lb (1 cup) 13-13-13, 0.6 lb (1.2 cups) 10-10-10, and 0.8 lb (1.6 cups) 8-8-8. After the tree has been in the ground for a year, this fertilizer application can be made while the tree is still dormant, just before buds begin to swell.

After trees start to bear fruit, adjustments to the fertilizer rate can be made based on shoot growth and other factors. In some years, no fertilizer may be needed. A fertilizer rate such as 3 lb calcium nitrate, 4 lb 13-13-13, 5 lb 10-10-10, or 6 lb 8-8-8 that provides 0.5 lb nitrogen per tree is about the most that would generally be needed in a year. Split the fertilizer between applications made just before bud break and after fruit set. If flowers are killed by a late freeze, skip the second application.

Even when you choose an appropriate apple variety for our area, disease and insect management are still likely to be a challenge. Dormant oil applications for scale insects, streptomycin sulfate or copper product applications for fire blight during bloom, and a combination of insecticide and fungicide applications to protect developing fruit may be needed.

Let me know if you have questions.

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Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).