Winter pruning is largely restricted to deciduous fruit trees and shrubs and those plants that flower on current season's growth. Pruning deciduous fruit trees during the winter months is not necessarily the best time of year to be doing so. Winter pruning will promote fast regrowth in spring but knowing the species is critical to pruning success.
Peach and nectarine trees fruit on previous season's growth while others such as apricot and plum trees have their fruit on wood that is two years old or more. What and where you prune in these cases will have a large influence on fruit yield.
Structural pruning or heavy pruning of deciduous fruit when they are dormant tends to lead to the emergence of water shoots during the spring growth period which in many cases is undesirable.
It is therefore best to undertake any structural pruning of deciduous fruit trees such as peaches, nectarines, plums, apricots, apples and pears immediately after they have finished fruiting in late summer. So keep the pruning saw and secateurs away from your fruit trees during winter.
Late summer pruning will allow deciduous fruit trees time to recover from pruning and rapidly seal wounds created from limb removal. This is particularly important for stone fruits which can suffer from a fungal disease called Cytospora Canker, commonly known as gummosis.
Winter pruning can render trees more susceptible to gummosis as the exposed cuts from pruning are slower to heal in cold weather resulting in infection by Cytospora spores. The symptoms of gummosis are the presence of an amber coloured resin or gum covering the bark at the point of infection.
A healthy tree will produce clear resins to seal areas of damage to prevent infection at the wound site. The important point to remember is the difference in colour between the gums that may appear on fruit trees. Clear gums require no action, but amber reddish gums indicate gummosis.
Gummosis is very difficult to control so the best line of defence is to ensure good cultural practices.
Prune at the right time of year, cutting out any weak or diseased branches and keep trees healthy with adequate nutrition and moisture in the growing season to improve vigour and ensure good yields.
