Pruning trees can be a complex art form, with each species of tree requiring different techniques, methods, environmental conditions and times of the year. Today we will be looking at when to prune stone fruit trees such as cherry trees, along with some problems which can occur as a result of pruning at the wrong time of year.
Unlike apple & pear trees, stone fruit trees such as cherry, plum and damson should never be pruned in winter, instead, they should be pruned in spring/summer either before or after flowering. Without regular, well done maintenance your fruit trees productivity will diminish over time and become harder to harvest as fruiting branches become higher and higher.
The first task when pruning any tree is to look for the three D’s, diseased, damaged and dead wood. These problems should be addressed before any structural or formative pruning is applied. Any diseased material should be removed, burned and your tools cleaned before carrying on. By following some basic hygiene principles you can help reduce the risk of spreading infections between your fruit trees (or any other trees in your garden).
Damaged wood is not just split branches caused by heavy fruit loads the previous year or strong winds, but also bark damage caused by rubbing branches. Rubbing branches, split wood and similar should all be removed along with any dead wood you may find.
Making your pruning cuts
When it comes to making your pruning cuts it is important to ensure you are using clean, well cared for and above all, sharp tools. Sharp tools will help you create clean wounds which are less prone to infection and look much better than ragged edges/split bark, which is often the result of using blunt tools.
To make your cuts look natural, you should aim to cut branches back to other branches which are at least 33% the size of the branch which you are removing. For example, if you cut a branch back which is 4 cm in diameter to a tiny twig which is only 1/2 a cm in diameter, then this is going to create a jarring sensory experience for your eyes, where as cutting back to a branch which is around 2 cm in diameter will help to keep a more natural looking tree.
Pruning in the rain?
Some tasks, such as dancing around umbrellas and spinning around lamp posts should be enjoyed in the rain, but pruning stone fruit trees is not one of lifes rainy day tasks. Pick dry days for your stone fruit pruning, as wet conditions leave your pruning wounds vulnerable to cankers and fungal infections such as Leucostoma canker. Cold and/or wet conditions make wounds slower to heal, compared to warm dry spring/summer days which allow wounds to heal faster and reduce the chance of fungal/bacterial infections.
Removing heavy/long branches
Removing branches which are very long/heavy in one fell swoop is not the best idea. Once you start cutting, the weight of the branch will start to pull at your cut causing the bottom area to tear as the weight pulls the branch down. Instead start by cutting the branch further up, then take off the small branch left and get a super clean wound.
Problems with winter pruning
When stone fruit trees are pruned in winter, they can develop silver leaf, which is often fatal to the tree come spring time. Silver leaf is a fungal disease (caused by Chondrostereum purpureum) which effects all stone fruit trees along with other fruiting trees such as apple. Fungal spores infect the wounds made in autumn/winter time mainly and leaves will start to turn silver in summer, after which branches start dying off.