The Pruning Series, 4.  If you choose to read only one of my posts on pruning, this should be the one.

Pruning cannot save every tree. This large Magnolia appears to have lost its main trunk  long ago and is now surrounded by suckers and sprouts with most of the base rotted out. The section growing to the right is full of rot and is leaning over the adjacent house. It is common for trees like this, heavily damaged and in decline to sprout this way.  Sprouts such as these are weakly attached to the trunk and the structural integrity of this tree is very compromised.  I would not be surprised if spring’s new grew will be enough added weight to cause it to collapse on the house.  The entire ‘landscape’ suffers neglect.  I’m sure no one is monitoring it.  Such is the case with most urban trees.

Whatever your goals for pruning may be you must always keep plant health first and foremost in mind.  In many cases, especially with high value plants in our landscapes, this might be our only reason to prune.  In any good pruning class the instructor will emphasize in some form, the dictum, ’First, do no harm!’ which is often attributed to the medical world’s Hippocratic Oath.  It seems fitting to me to do this as both are dealing with life and promoting good health, only with horticulture and gardening our ‘patients’ are plants.  All organisms have a characteristic, genetically determined structure, that when compromised threatens its health.   All organisms experience stress and, if within limits, respond by strengthening their structure.  Expose them to excessive stress and physical damage occurs.  Storm damage, breakage, vandalism, branch failure following the growth of weak structure, a ‘burden’ of dead wood, diseased tissue, all add to the stresses on a plant and can all be relieved by good pruning…or exacerbated by poor or overly heavy pruning.  Timing can also be a factor as it can disrupt the natural growth cycle causing a delay in the plant’s acclimation to cold process. Continue reading →