Your orchard may be set up in an ideal location, your soil is perfect and your fruit trees are thriving and producing wonderful new growth but the fruit set on your plants is minimal or non-existent. While your orchard may be thriving it is lacking your involvement. Young trees, like unruly children, need to be guided, pruning is needed and supple branches need to be directed in the right direction.
We recommend two prunings per year. The first one is done in late June or early July. Within a few short months, your trees will go from being bare-branched and leafless to shaggy and unkempt-looking specimens. Each of the growing points will produce 1-4 feet of growth depending on the variety. Early summer pruning curbs this mad growth and directs the plant's energy into fruit bud production rather than leaf production. Follow the supple new branches back to where the growth originated that spring and trim back each branch to maybe 3 or 4 leaves. Behind those remaining leaves the buds will transform into fruit buds rather than leaf buds.
Not only does this summer pruning reduce the tree's size dramatically and keep it small, but it also increases the density of production so that the branches will be laden with fruit in the following year. Sometimes this early summer pruning is enough to slow the growth of the tree but occasionally a second pruning in August is required to once again reduce the size of the new growth and discourage leafy stems without fruit buds to form. Pruning in this way will be sufficient to maintain an apple tree in a balcony pot for many years.
The second pruning happens when the tree is dormant. The leaves have fallen and the branch structure can be seen. Broken and diseased branches can be removed while supple young branches can be tied with soft nylon twine to direct them into open spaces in the tree’s canopy. If there are vast quantities of fruit buds, as there will be in more mature trees, some of the branches can be thinned to allow more light and air to the surrounding branches. This pruning in winter generally does not remove nearly as much growth and material as the summer pruning did but it is more deliberate.
It matters where the cut is made on a branch. A new branch will form at a bud below the cut that was made. If a branch is trimmed down and the bud below the cut is facing into the center of the tree, the new branch that forms will grow in that direction. To encourage air and light in the center of the tree, each branch should be trimmed to a bud facing away from the center. One exception is when there is a gap in the tree where a branch has been removed, then it is best to cut an adjacent branch down to a bud that faces the opening to direct the new branch in the direction of the void.
Pruning is an intervention but it is good for the tree, directing the growth and promoting heavy yields of fruit. A tree that gets little pruning will be unbalanced and top-heavy with branches that break easily under a load. I encourage novices to attempt pruning, good skills become intuitive with practice, and a tree that is pruned heavily with some errors can easily be repaired and redirected at a future pruning. It is easier to repair a frequently pruned tree that had incorrect cuts, than to repair a neglected tree that was never pruned.
With proper pruning, fruit yields will be very abundant. This can lead to too many small fruits developing on a plant and in some cases a phenomenon called biannual bearing. In the first case, the fruit set is so good that there are many small fruits on the plant. In the second case, the fruit is so abundant that the tree proceeds to produce every other year and takes a rest in the alternate years. The solution is another form of pruning called fruit thinning. Many young developing fruits are removed from the tree leaving a few fruits evenly spaced down the branches to promote fewer but larger fruit to form.
