By Tom Ogren
Like most people who grow deciduous fruit trees (apples, peaches, plums, cherries, apricots, etc.) I used to do lots of serious heavy pruning every winter.Each winter I would head back dozens of those long, tall canes that had grown the year before. On some trees, plums in particular, each year I’d often find myself cutting back a huge number of new branches, many of them well over six feet in length. I occasionally wondered: Isn’t this hard pruning cycle putting a big workload on the tree? Each summer the tree pours all its energy into growing those overly long new branches, and then each winter I’d chop them back, trying to keep the tree’s overall height under some semblance of control. And then too, despite my best intentions and hours of work spent pruning, each season the trees still seemed to be a bit taller than the year before. However, each winter for decades I kept up this hard winter pruning, working with the standard conventional wisdom that it was necessary in order to have a decent tree and a good set of fruit. At the time it made perfect sense to me. Because of apical dominance, when a tip is cut off, the next bud back from what is now the tip, this bud will normally sprout next. The topmost bud on any strong branch has high concentrations of the natural growth hormone, indole acetic acid (IAA). When we prune grapes (which unlike most pomes and stone fruits, set fruit only on new wood) we have to prune the last year’s wood hard. We cut back to a few large, strong buds. The lower down on the branch a bud is, the larger and stronger it is. Thus, heavy pruning makes plenty of sense with grapes, or others that bloom on new wood, figs, mulberries, and roses. But does this same sort of hard pruning make sense with most fruit trees, trees that do not set their fruit on the current season’s wood?
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