Superb Management of Apple Trees - Artists!
Late winter is the best time to prune mature apple trees. If you’re buying young ones in the spring, they may or may not need pruning, depending on several considerations. Trees need to be pruned for best yields and longest tree life. How much to prune will depend on what type of tree you have.
Whether you have existing trees, or are buying new ones (remember when buying to get at least two different trees that are compatible for cross pollination), make sure you know the ultimate size. Dwarf (7 to 10 feet) and semi-dwarf (12 to 15 feet) may need less pruning than the traditional and now less common standard trees (more than 15 feet when mature).
The first branches to look for in pruning can be remembered by the 2 C’s and 3 D’s. Remove any that are crossing and rubbing on each other (keeping the most vigorous or branches pointed in the desired direction), and those that are crowded (this allows more light and air into the center of the tree, increasing growth and reducing diseases). Then look for pruning out any branches that are dead (discolored, no signs of buds, brittle), diseased, or damaged (such as broken by ice storms).
Trees should have well-spaced “scaffold” branches. These are the main branches that arise off the trunk, that help form the canopy, and from which lateral branches arise. These should be spaced up the trunk vertically 8 to 12 inches apart, 3 to 4 inches for dwarf trees. They should not arise off the trunk directly across from each other, nor directly above another branch.
The best branches are more horizontal than vertical. They’re stronger, less apt to break in wind and under fruit loads, and produce more fruit. So remove the more vertical ones. If many are vertical, you can use some tricks as growers do, either weighting them down slightly for the season, or place thin posts between branches to space them. Different cultivars (cultivated varieties) will have different growth habits. For instance, ‘Red Delicious’ tend to be more upright, ‘Jonagold’ and ‘Liberty’ tend to be more spreading.
Another term to know in pruning apples refers to the system. Most will be pruned to a “central leader.” As it indicates, this is simply leaving a main terminal shoot, and pruning off any on top near this that are competing to be the leader. It results in a cone-shaped tree like a Christmas tree shape. With such pruning, dwarf and semi-dwarf apples will be stronger and bear fruit sooner in their life. It also is good for weak trees, or those growing on poor soil.
If buying a young tree, it usually has already been pruned to set up this central leader habit. Look up the stem for the main upright leader coming off at a slight angle. This is where the original trunk was pruned back to an upward-facing bud, which now has grown into this stronger leader.
For established trees, if the leader grew over 18 inches the previous year (you can tell this by the lighter colored wood), prune off about one-quarter (cut off 4 to 5 inches of tip growth). Cut back to just above a bud, which will result in a new leader taking over, as described for young trees. More scaffold branches will grow too.
If the leader grew less than 18 inches last year, cut back both it and scaffold branches in order to stimulate more growth. Skipping cutting back the leader is fine if you want a more upright tree more quickly, or earlier fruiting on dwarf trees (but, at the expense of fewer branches and so less fruit overall).
A variation on the central-leader system is the modified-leader. With this system, once the tree is about 7 feet tall, cut back the top branches to about 6 feet. Then cut back similarly each spring. This results in a main trunk most the way up, which then branches into several scaffold branches, making the overall shape less conical but still upright. Use this for particularly vigorous trees, or to keep standard trees shorter (and so easier to manage).
Keep in mind that once a young tree has the correct shape and branch orientation, it will need little pruning compared to more mature trees--- merely watch for the 2 C’s and 3 D’s, and pruning for shaping. Too much pruning of young trees will lead to excessive growth, and this will delay years to good fruiting. The more severe the pruning, the more growth the tree will produce. This may be desired if a tree is weak. But if a tree is vigorous, it’s better to cut back on fertility to reduce the growth rate.
A common mistake of beginning pruners is to cut off too much of last year’s growth, resulting in little to no fruit. Avoid pruning once the tree starts to leaf out, as this may interfere with flowering and so fruiting. Good times to prune in later winter are on days above freezing, not only as it is easier on the pruner but on the tree. Cuts made to frozen branches often result in injury and dieback.
