Why the 1/3 Rule?
For established shrubs and small trees, moderate pruning has the effect of stimulating new, vital growth.
Plants live in a balance between the above-ground and below-ground parts.
The Spruce / Jayme Burrows
Once suckering begins, it has a tendency to continue for quite some time.
Too little pruning, on the other hand, does little to stimulate any new growth at all.
An established plant is one that has fully overcome its transplant shock.
With larger shrubs that have been transplanted, this shock may last several years.
Pruning trees regularly is still important, however, since it makes them less susceptible to wind damage.
For most shrubs, late winter or early spring is the best time to prune.
The plants are still in full dormancy at this time but are just preparing to produce new growth.
With a vigorous, established shrub, begin by removing anydead, damaged, or diseased wood.
Next, remove any crossing branches where the bark is rubbing.
Remember to be bold when practicing the 1/3 rule.Its important to remove enough wood to achieve your goals.
For new gardeners, the tendency is to prune too little and fall short of the ideal.
For these shrubs, some experts recommend a very severe form of pruning, known as rejuvenation pruning.
This involves cutting the entire shrub off at a level just six to 12 inches above the ground.
Late winter or early spring are some of the best times for pruning shrubs and small trees.
During this time, most plants are still dormant.
It also helps shape plants and revitalizes them, keeping them healthy.
Over pruning a shrub or tree can actually stunt its growth or damage it.
