Something About Fruit Tree Pruning
The most well attended class at Home grown Gardens every year is the fruit tree pruning class. Most of us are confused, too timid a pruner or just don't know where to start. There are whole books devoted to pruning fruit tree, so I can only get so much information out is a short article. First I recommend the OSU Extension publications:
· PNW 400 Training and Pruning Your Home Orchard, Revised July 2011
· EC 819 Growing Tree Fruits and Nuts in the Home Orchard
· EC 1005 Pruning to Restore an Old, Neglected Apple Tree
Also for help understanding Backyard Orchard Culture go to www.davewilson.com and look up the page and you tube help on this method of managing the home orchard.
One factor not well understood, and maybe not agreed upon by all professional is to utilize summer pruning for size control of fruit trees. There are specific objectives to dormant pruning, working to strengthen the structural integrity of the tree and, encourage fruiting wood, removal of unwanted growth and more. Summer pruning helps manage the size and limit the quantity of spring shoots after a heavy winter prune.
There are two systems to training a young tree, the open center, or what I often call the vase shape, and the central-leader, or Christmas tree shape. Both can work for a backyard orchard set up. Some may want to consider an espalier form or even a hedge row form. The PNW 400 has good information of training for these forms.
To me one key criteria to managing your fruit trees is size control. How high do you want to climb a ladder to prune, harvest fruit and spray your trees? I like the idea of doing all my work from the ground, the higher I fall off a ladder the more potential damage I do to myself. I like to idea of keeping the trees a manageable height of 8-12 feet. Even 12 feet tall is pretty tall, but ,you can do much of the pruning work with long reach pruning tools.
The challenge for many is when they inherit a overgrown apple tree, or any tree for that matter, and now you want to develop fruiting wood down low where you can reach it. This effort can take years to develop the tree to the size you can work from the ground to manage it. Sometimes the decision to remove and start over with a young tree you can train is a better option.
When it comes to how much to prune you need to understand where the fruit is borne on the tree, in other word what kind of wood bears fruit. Here is a brief description where the fruit is borne:
· Apples bear on spurs that last many years
· Pears fruit also of spurs.
· Plums and Prunes bear on spurs from 2 years and older.
· Peaches bear on 1 year old wood.
· Figs bear on current season wood, black figs also bear on older wood.
· Apricots bear on one year old wood and older, some spur development.
· Persimmons bear on current season growth.
· Grapes bear on current season growth.
· Cherries bear on older wood from short spurs.
· Blueberries bear on one year old wood.
· Black berries bear on last year's growth.
· Raspberries also bear on last year's growth
A lot of the work on a mature apple tree is managing the sprouts/whips. When you are keeping an apple tree at 12 feet, and it has the genetic predisposition of being 25 feet, it will always be trying to be 25 feet. Controlling the height becomes a battle of the whips. Since the fruit is born on spurs on mature wood no loss of fruiting wood occurs when you cut off the whips, however, as a tree gets older the spurs may stop being productive and the need to restore fruiting spurs becomes a component of the pruning strategy.
Peaches on the other hand bear on one year old wood and not on older wood on spurs, therefore you need to renew the growth each year so you have fruit. A peach requires mostly thinning pruning cuts, removing up to 2/3rds of last year's wood. If you don't do this each year the fruit bears further out on the branches, eventually leaving the branches venerable to severe breakage.
Persimmons, grapes, and figs bear fruit on current seasons growth, so as long as the tree or vine is healthy it will grow wood and bear fruit on that wood the same year. These can be more forgiving if you accidently take off more wood that you intended to.
Whatever the kind of fruit tree you will always want to start out removing dead or weak wood first. Make the cuts necessary for height control then cut out the wood necessary to manage the fruiting wood.
Refer to the OSU Extension publications for more detail and instructions on pruning. Don't be timid, do the pruning that is needed, but do your homework first so you have the confidence to make the right cuts. Remember, once you cut it off, you can't put it back on.
Home grown Gardens
February 4, 2019