ARTICLE - How to Prune Trees or Shrubs

Why should you prune your trees and shrubs?

  • To train the plant
  • To maintain plant health
  • To improve the quality of flowers, fruit, foliage, or stems
  • To restrict growth
  • Safety

When do you prune trees and shrubs?

  • Pruning can actually be done at any time of the year; however, recommended times vary with different plants. Continual improper pruning results in damaged or weakened plants.
  • The best time to prune most plants is during late winter or early spring before growth begins. Dormancy pruning reduces the risk of pest and allows trees to take advantage of full growing season for closing and compartmentalize wounds. There are exceptions to this rule.
  • The least desirable time is immediately after new growth develops in the spring. A great amount of food stored in roots and stems is used in developing new growth. This food should be replaced by new foliage before it is removed; if not, considerable dwarfing of the plant may occur. This is a common problem encountered in pruning.
  • Limit the amount of pruning done late in summer as new growth may be encouraged on some plants. This growth may not have sufficient time to harden off before cold weather arrives resulting in cold damage or winter kill.
  • Prune plants damaged by storms or vandalism or ones with dead limbs as soon as possible to avoid additional insect and disease problems that may develop.
  • Blooming plants should be pruned after bloom. Crape myrtles are done in late winter removing suckers and lower growth only in spring and summer.
  • Tree growth is maximized if pruned just before bud swell.
  • Dormancy pruning reduces the risk of pest and allows trees to take advantage of full growing season for closing and compartmentalize wounds.
  • Don't prune transplanted plants until establishment a year or two after.

How to prune trees and shrubs?

Cuts made while pruning are wounds to a tree and the way they protect the rest of tree from pest and early decay is by closing and compartmentalizing the wound. So always use the plan approach to pruning when you prune.

Pruning should follow a definite plan. Consider the reason or purpose before cutting begins.

The next step in pruning is to make any training cuts needed. By cutting back lateral branches, the tree or shrub is trained to develop a desired shape, to fill in an open area caused by storm or wind damage or to keep it in bounds to fit a given area. To properly train a plant, one should understand its natural growth habit. Always avoid destroying the natural shape or growth habit when pruning unless maintaining a close watch over the plant, for after a period of time it attempts to assume the more natural growth habit.

Make additional corrective pruning to eliminate weak or narrow crotches and remove the less desirable central leader where double leaders occur. After these cuts have been made, stand back and take a look at your work. Are there any other corrective pruning cuts necessary? If the amount of wood removed is considerable, further pruning may need to be delayed a year or so. Remove water sprouts unless needed to fill a hole or to shade a large limb until other branches develop.

  • Thinning removal of connecting branches to point of origin or shortening the length of a branch by cutting to a lateral.
  • 'Heading' is cutting back portions of shoots. Where each shoot is headed, bud breaks create two, three, or 4 shoots. Continual heading is bad for the plant as it creates too much canopy.
  • 'Rejuvenating' is cutting back to ground leaving a few canes creating new growth from the bottom up. Large leaf hollies and azaleas and ligatures do well with this. Small leaf hollies don't do as well.

Cuts: To encourage rapid healing of wounds, make all cuts clean and smooth. This requires good, sharp pruning equipment. Do not leave stubs since they are usually where die back occurs. Avoid tearing the bark when removing large branches. The following provides some specifics on pruning techniques.

  • When cutting back to an intersecting (lateral) branch, choose a branch that forms an angle of no more than 45 degrees with the branch to be removed. Also, the branch that you cut back to should have a diameter of at least half that of the branch to be removed. Make slanting cuts when removing limbs that grow upward; this prevents water from collecting in the cut and expedites healing.

To "open" a woody plant, prune out some of the center growth and cut back terminals to the buds that point outward. In shortening a branch or twig, cut it back to a side branch and make the cut 1/2 inch above the bud. if the cut is too close to the bud, the bud usually dies. If the cut is too far from the bud, the wood above the bud usually dies, causing dead tips on the end of the branches. When the pruning cut is made, the bud or buds nearest to the cut usually produce the new growing point. When a terminal is removed, the nearest side buds grow much more than they normally would, and the bud nearest the pruning cut becomes the new terminal. If more side branching is desired, remove the tips of all limbs. The strength and vigor of the new shoot is often directly proportioned to the amount that the stem is pruned back since the roots are not reduced. For example, if the deciduous shrub is pruned to 1 foot from the ground, the new growth will be vigorous with few flowers the first year. However, if only the tips of the old growth are removed, most of the previous branches are still there and new growth is shorter and less vigorous. Flowers will be more plentiful although smaller. Thus, if a larger number of small flowers and fruits are desired, prune lightly. If fewer but high quality blooms or fruits are wanted in succeeding years, prune extensively.