Tree Pruning

Tree Pruning -  A proper pruning cut

Tree Pruning is, for most people, an intimidating and daunting task. However, with a little understanding and knowledge, keeping your trees in tip-top shape doesn’t have to be such a fear-inducing project.

Fall to midwinter is, in most cases, the optimum time for tree pruning.  Here are a few tips to help you as you work this fall and winter to maintain your trees and shrubs in your landscape.

Take a step back.

I always urge caution when pruning trees and shrubs.  Over pruning is a common problem.  Most trees do not need heavy pruning every year with the exception of some fruit trees.  Some trees may need to be judiciously pruned to eliminate lower branches that have become a hindrance or are in danger of contacting your home or other structures.  Removing too many lower branches can seriously weaken or even kill an otherwise healthy tree.

When to Prune?

Landscape trees can be pruned anytime.  The best time is from fall to winter.  Fruit trees should be pruned from mid-winter up until buds break.  Peach trees should only be pruned just before the buds break in the spring.  Pruning peach trees will cause the buds to break and if done too early will almost certainly result in no fruit.

How much do I prune?

Pruning trees is as much art as it is science.  Every species of tree has its own character and its own distinctive look.  These characters and distinctive look should be considered when selecting trees for planting in your landscape.  Nothing is more frustrating than trying to change this character and look by pruning.  It won’t work, and you can seriously stress the tree or even kill it. 

In general, removing lower limbs to any great degree is a bad idea.  You may think it looks good, but it is stressful on the tree.  Here are some general rules of thumb for pruning landscape trees.

tree pruning - DON"T CROP
  • Remove dead and diseased limbs, broken or damaged limbs and any crossing limbs.
  • Any limbs that grow back toward the heart of the tree canopy should be removed.
  • If limbs are dangerous or physically interfere with buildings, remove them judiciously.
  • Avoid leaving V-shaped crotches in trees.  These cavities can become traps for debris and water and are havens for insects and disease.
  • Do not “thin” a tree.  Removing foliage stresses the tree and opens it up to attack by pests and disease.  Never gut the interior of the tree canopy.
  • Never ‘CROP” a tree.

How do I prune?

First, always make sure your tools are sharp and clean.  Dirty tools can spread disease from plant to plant.  Dull cutting tools bruise and damage the wood structure and leade to infestations and rot.  Always use the appropriate tool for the job you are performing and the size of pruning cut you are making. 

Never make flush cuts when pruning limbs.  Cuts should leave at least 1/16th of an inch but no more than 1/8th of an inch of the branch where it meets the trunk.  There is a swelling on the branch close to the trunk.  This swelling is called the branch collar and under no circumstances should the pruning cut be made into this collar. Cutting into the collar can damage the protective zone between the trunk and the branches leaving the entire tree open to infection and pest infestation.

bad pruning practises

Cuts should always leave a round wound just outside the branch collar.  The branch collar will soon begin to overtake the wound as the tree begins to heal.  Limbs which have been pruned that don’t heal were probably pruned to close to the tree collar or too far if a deadwood stub remains.  Fruit trees are particularly susceptible to this kind of damage. 

Tree Pruning - Callus forming

Treating Wounds on Trees

Studies have shown that painting pruned trees or applying a dressing to the pruned area are of little or no value.  These treatments can be harmful in the long run by slowing the healing process.  Adding such paint or dressings can impede the formation of the callus, the growth that the tree produces to try and cover the wound.  Trees produce lignin.  Lignin is the trees answer to wounds and does almost the same job as white blood cells do in humans.  The same studies mentioned above saw the best healing on trees when the wound was left exposed to the air.

Conclusion

Prune carefully and in a limited fashion.  Trees are one of the few living parts of your landscape that can appreciate over time, adding value to your home and property.  Treat them with care and respect.

For more information about organic gardening and landscape maintenance see our article library here.