A back yard orchard can provide year-round harvests of delicious tree-ripened fruit. Pruning is important to maintain plant health and assure longevity. Different pruning styles are often applied to different fruit trees. Single-leader, modified-leader and open-crown or center pruning styles are often used. This article describes the open-crown style which is an easy pruning method that can be used on just about any fruit tree.
Pruning Tools – Pruning tools, such as bypass pruners must be sharp to deliver proper cuts. To prevent the spread of possible disease, pruning tools must be sanitized with isopropyl alcohol between every single tree.
Scaffold Branches – Newly planted fruit tree specimen which may already be several feet tall should be pruned from about knee-height. In general, cuts must be made just above outward buds so that developing branches grow outward from the centre of the tree. Ideal are four 16 inch long (scaffold) branches that point at all four directions. They should be about in a 45 to 60 degree angle from the trunk which makes them flexible enough to carry heavy crops without breaking. Steeper branches can be trained by bracing which forces them to grow in the desired angle. The center leader needs to be cut off at its collar, close to the trunk. And that’s all that needs to be done for the first season.
Winter Pruning – In the following year’s late winter, or just near the end of dormancy, the tree should be inspected for the previous summer’s growth. Long branches should be pruned back about three quarters of their length and again, in order to maintain an open centre – cuts must be made just a bit above outward buds. An important step anytime during pruning is to remove diseased or dead branches.
Sometimes it can be difficult to tell between heathy and dead branches. A simple trick is just to gently scratch the bark to determine if it is green underneath and alive or brown and brittle and dead. The dead part of a branch can then be cut back to where it is still alive at an outward bud so it can heal over. There are two types of cuts being applied here – heading cuts just above outward buds shorten branches and thinning cuts at the base or collar remove branches.
It is important to focus on establishing and maintaining the desired shape of a fruit tree. In this example, the aim is for an open-crown or centre, like the shape of a wine glass. This pruning style provides good aeration and open space around branches and the developing fruit which can reduce the possibility of disease development.
Looking at the bottom’s four scaffold branches, all new crossing , crooked or vertical branches or those growing toward the centre should be removed. The lengths of the grown scaffold branches can be cut back by one third to maintain the desired shape of the tree. This can be repeated every late winter or depending on growth rate, in early summer. It is recommended to spray fruit trees to prevent diseases from harming or even killing a tree.
Bylaws in the Okanagan require fruit tree owners and growers to treat their plants against codling moth, which is a big problem in commercial orchards. Prevention can be achieved with dormant spray applications in late fall after leaves dropped and in late winter before dormancy ends.
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