Gardening Today: Pruning Techniques
Where To Make Your Cuts
When you approach a plant with shears in hand and pruning on your mind, either to cut flowers, improve a plant's shape or whatever, remember this: Always cut to something. You can cut to a lateral branch or a bud, but never leave a stub. This is probably the most important and neglected concept in pruning. Think of a branch as a conveying tube; if you make a cut, leaving a length of wood or stub above a lateral branch, bud or point of growth, there is no reason for water and nutrients to enter it. This stub is no longer an active part of the plant, so it withers and dies. Decay starts at this point and begins to travel down into the plant causing rot as well as a favorable condition for borers and other harmful insects. As a rule, pruning cuts made 1/8-1/4 inch above a bud or lateral branch are adequate. Any less can destroy the bud when the wound dries; more than 1/4 inch leaves excess wood, making the plant susceptible to rot and decay. Cuts are to be made at an angle (30-45 degrees) rather than cut off flat or square. This will allow moisture to run off the wound as opposed to a surface that holds water, allowing decay and rot to begin.
Also, select a bud or branch facing outward or toward an open space. With the theory of apical dominance in mind, you can be certain of the direction of new growth. If the cut were made to an inward-turning bud, the new growth would eventually cross and rub other branches. This rubbing damages tissue and prevents air circulation and light penetration. This type of growth occurs frequently enough in nature without being encouraged by pruning.
When to Prune
Light pruning can be done almost anytime of the year (i.e., pinching out terminals to make a more compact plant, etc.). When large cuts and branches are to be removed, the winter months are best. Bear in mind that pruning actually stimulates growth to the remaining buds. If this is done late in the summer or growing season, the plant will respond by sending out new succulent growth. This new growth is very susceptible to fall frost damage. Heavy pruning should be done while the plant is dormant allowing the cuts to callus and heal over before the sap flows freely in the spring.
Some trees (i.e., birch, sugar maple, etc.) are called bleeders in that they secrete much sap when large cuts are made. It is suggested that bleeders be pruned after leaves are out and plant has reached its peak in annual growth. Pruning paint will not seal or stop a bleeder from dripping.
Where to Start Pruning Trees
There are several steps to follow when attempting to prune a tree. These techniques will comprise the major portion of your pruning, leaving small detail work for personal preference or imagination.
Removal of all dead and diseased wood. This helps prevent rot and decay and eliminates entry points for boring insects.
Remove crossing, rubbing branches. This wood will eventually damage tissue, causing rot and decay.
Remove branches growing straight up or turning inward toward center of tree. This will allow air and sunlight to penetrate the tree canopy, producing healthier growth and fruit development.
Remove weak or poor branch crotches. A strong crotch is at an angle (45-90 degrees). This will support heavy foliage and fruit production and minimize staking, guying and artificial supports.
Elevate lower branches. This allows easy access for mowing and cultivating under and around the tree canopy.
After completing these five steps, stand back and look at the remaining material. If one branch or side of the plant is larger or out of proportion, head back to a bud or lateral branch turning the desired direction to balance the canopy.
Removal of Large Branches
To avoid ripping and tearing of bark, remove heavy branches with three cuts. Start out from crotch at least six inches and make your undercut about halfway through the branch. Your second cut will fell the branch free of the trunk. The third cut removes the remaining stub with no injury to the trunk.