Orchard Origins was back at Houghton farm this week to finish pruning some two year old apple trees. While we were there, the farmer was keen to get our thoughts on his attempts at pruning a small orchard at the entrance to the farm.
The orchard, a mixture of apple, pear, plum, cherry and greengage, had not been pruned for a number of years and most of the trees had become severely overcrowded. Pruning had successfully opened up the centre of the trees which will improve air circulation and allow in more light.
But, there were also some useful learning points that we thought would be helpful to share on the blog.
- Stone fruit trees, such as cherry, plum and greengage, should only be pruned in the summer to avoid silver leaf disease.
- Restrict branch removal to one third of the total canopy in young vigorous trees; a quarter in old trees
- When cutting a large branch back to another branch [rather than the trunk] ensure that branch is at least one third the thickness of the branch you are cutting. We will blog more on this.
- Always cut branches at the branch collar.
So what and where is the branch collar?
The collar is the point where the branch attaches to the trunk or to another branch. It’s usually fairly easy to spot. Look for the swollen area that has a ridged or wrinkled appearance.
The branch collar is the tree’s own natural defence against disease that prevents the trunk becoming infected. When the tree detects that a branch has been broken or cut it produces callus wood to seal the wound. In this way, the tree isolates the damage and stops decay organisms affecting the rest of the tree.
When removing a branch, it should be cut back to the trunk flush with the outer edge of the ridged area. This preserves the branch collar and allows it to do its work sealing the wound.
Do not apply a wound paint to the cut. Not only is it a waste of money, but research has shown that far from preventing rot it can exacerbate the problem by interfering with the tree’s own defence mechanisms.
When a tree has been pruned hard, it will fight back by forming buds around the site of the wound. Leaving a long stub stimulates the tree to produce fast-growing upright shoots known as water shoots or sprouts to replace the branch that has been removed. This diverts energy away from fruit production. The shoots need to be removed in the summer. Cutting the stub back to the branch collar will prevent this which is good for the tree and saves you time down the line.