There are several reasons to prune plants:

Nicely pruned Hawthorne

It takes well-timed pruning to get a tree with such a nicely balanced look.

Photo Credit: Joe Seals

  • To control a plant’s size or form and enhance its beauty and character (aesthetics).
  • To promote a healthy plant by removing existing damage (perhaps caused by mechanical mishaps, disease, etc.)
  • To improve flowering and fruiting by increasing air and light circulation – which also helps prevent diseases.
  • To direct or confine growth to prevent potential damage that can be caused by overlapping branches and poor crotch angles.
  • To stimulate new growth on older plants that have slowed in leaf and branch production, or to simply fill in bare areas.
  • To prevent personal injury or property damage due to out-of-control branches.
  • To train young plants for bonsai, topiary, espalier or other types of special plant training techniques.

When should you prune?

This depends on the situation.

Corrective pruning, due to injury or dead tissue, should be done as soon as the problem is evident.

Serious pruning – when large limbs need to be removed – should be done during the dormant season (winter for typical deciduous plants) or depending on the plant’s flowering time. For flowering time scheduling, follow the “May Rule:” If the plant blooms BEFORE May 1, prune immediately after flowering has ended. Flowers of these plants are produced on old wood or last year’s growth. (Examples are spring-blooming trees.) If the plant blooms AFTER May 1, prune during the dormant season. Flowers of these plants are produced on new growth or current year’s growth. (Crapemyrtles are a good example.)

There’s just one exception to the May Rule: All hydrangeas (which are summer bloomers) should be pruned immediately after flowering.

All other pruning is best done lightly throughout the summer or during your region’s main growing season. Fruit trees should be pruned in winter to train tree growth and to shape the tree, as well as to open up the center of the tree for light, or to remove unwanted or upright current-season growth.

Prune non-blooming ornamental evergreen plants in late winter or spring. (Most shade trees and hedges would fall into this category.)

Pruning isn’t necessary for all plants. But those plants that do need it are much better off for it, and those plants that don’t need major pruning can still turn into beautiful specimens with just a little tweaking with your pruning tools.