This is the second part of what turned out to being a magazine length article on the recent 2 1/2 hour pruning session MSUE Fruit Tree Specialist, Bob Tritten gave at the Stanger farm.
Getting a bird’s eye view
Pruning often strikes terror in the heart of the average backyard orchardist. The most common fear is damaging or worse still, killing the tree by cutting off too much! Pruning is an art, but it can be learned by watching a pro in action to see how far you can go and why certain things are done. Then it is a matter of practice and common sense. The results are well worth the effort in more manageable and productive fruit trees.
Decision time – what to keep.
The most often asked question at the Conservation District plant and tree sale, is “how do I prune up my new fruit tree!” I hope the following points will help, as they are a brief summary of what Bob was asked during his presentation.
If you still want more information, there is an excellent chapter in the Master Gardener handbook on fruit tree pruning – or go online and do a search of MSUE or any extension site for further research.
Why prune: Fruit trees unlike ornamentals, are pruned to make them more manageable, promote healthy growing conditions for tree and fruit, and more productive. While some pears and apples can be seen in an espaliered form as a landscape accent, this is not the desired method of pruning for a backyard orchard. Fruit trees need air and light for optimum fruit development and a reduction of fungal diseases associated with poor air movement.
When to Prune: This was the most asked question. Each tree should be pruned annually. Bob recommends March and beginning April as being the optimum timeframe for pome fruit, (apples and pears) – while late April to early May as being acceptable for stone fruits (peaches and apricots). The late winter or early spring cold weather offers ideal conditions for this kind of work. Most commercial orchards start this process in late December or early January, due to the large volume of trees needing attention. It is best not to prune during active budding.
Heart shaped young peach
What to Prune: Bob stressed the need for developing a strong structural skeleton (scaffold) for the tree to be the most productive. He recommends a modified central leader form for all pome fruits and an open center, heart shaped structure for stone fruits. After making the choice of the branches to keep to establish the scaffold, the annual pruning shifts to being a maintenance chore. Dead wood, watersprouts, suckers, inward growing and crossing branches all should be removed.
Watersprouts can be removed up to mid summer. This should be done religiously, as they take up sugars that the tree could otherwise put into fruit production.
Pruning Watersprouts
Bob demonstrated an alternate method of watersprout removal, by leaving some as stubs to provide some shading leafing. These would then be removed the following year.
He cautioned against clipping the ends of the branches when shaping the tree, as this just leads to excessive sprouting.
Keeping stubs for shade
What about Frost Damage: With recent low temperature hovering around 33 deg, this is not a problem for the buds. But when this session was conducted a little over a month ago, it was. Two successive nights of 26 to 29 deg frost had caused considerable damage to the buds. The lowest temperature buds can tolerate for a short period is 28 deg without irreversible damage. When the bud dies, there is no fruit! Using a small pocket knife, he carefully pared the surface of a couple of random buds to reveal a thin brown layer – the sign of frost damage and a dead bud.
What about Fruiting: Surprisingly dwarf stock trees begin to fruit within three (3) years. Bob advised removing this fruit to allow the tree time to establish its structure. Peaches are relatively short lived trees – about ten (10) years is the average productive life, as they are susceptible to a variety of killing cankers.
Peach fruiting branches
Care should therefore be given to preserving the following year’s fruiting branches when pruning. The same applies to pome fruit – so just do not hack away as if you were pruning an ornamental! Most fruit trees will self-thin if conditions are not ideal for fruit development. Fruit clusters should be examined and thinned according to branch strength. It is important there be leaf clusters nearby for maximum sugar uptake.
What about Renovation: A frequent topic of concern to the backyard orchardist who has inherited an overgrown, neglected fruit tree and wants to return it to productivity. Bob’s approach is to take a long view of the tree, particularly one not grown on dwarf or semi-dwarf stock – and see if the scaffold branches can be identified. An old tree grown on regular stock will require ladder work to harvest and prune. So a decision has to be made if the tree is to be saved outside of aesthetic or sentimental landscape appeal.
Identifying scaffold branches
If it is to be renovated, start by removing the usual dead wood, watersprouts, ingrowing and crossing branches – but nothing major. This work is just to expose the bones of the tree, and should not be more than 20% by volume. The remaining renovation pruning should be over a three (3) year period and with no more than 30% removed annually. The object of all this work is to improve the scaffold branches of the tree. Care should be taken to ensure that the tree has adequate leafing branches to provide the sugars for regrowth purposes. You should not expect or encourage any fruit production during the initial renovation process. After the tree has been stabilized, fruiting should resume.
Watersprouts can be trained to fill in bare spouts by bending them into place with ropes secured by stakes. To reduce the height of a mature neglected tree, Bob recommended making sure that there are sufficient well placed lower branches to form a scaffold. Often viewing the tree from a ladder will add a better dimensional picture of what is to remain and what has to go. This is the reason why well placed watersprouts may be essential to restoring the shape of the tree.
What about Branch Kerfing: Stressing the need to have a scaffold branch at the correct angle to the trunk, Bob demonstrated this unusual technique on a 2″ dia limb that bending with a rope and stakes would be impossible. He made five (5) closely spaced saw kerfs half way through the underneath side of the branch. With some of the tension removed within the wood, he was able to bend and pull down the branch without breaking. The bent branch was then secured with a rope and stake. The wounds heal in about a season and do not require any form of dressing.
Kerf cuts on branch
Rule to remember: Bob’s mantra is you want to be able to throw a football through a well pruned fruit tree! Or have a good sized bird fly through the center. Open and airy are the two words he stressed throughout his presentation!
Jennie will do a follow up article with more specifics on the pruning and care of the common fruit trees we find in our backyard orchards.
Once again we should thank the Conservation District for sponsoring events like this for the education of the general public. This community involvement is all the more important, as we no longer have an extension walk in diagnostic clinic. Our thanks also go to Jennie Stanger for teaching these annual classes and for hosting this special guest.
Frank.
Monroe County Master Gardener Association 