The point of doing this is to keep your plants healthy and encourage them.
Pruning changes the form and growth of a plant. Pruning can also be considered preventive maintenance for both insect and disease damage. Many problems may be prevented by pruning correctly during the formative years for a tree or shrub. The late dormant season is the best time for most pruning. Evergreen Shrubs. Prune evergreen shrubs, such as juniper and yew, in late March or early April before new growth begins.
Light pruning may also be done in mid-summer. Avoid pruning evergreen shrubs in the fall. Fall pruned evergreens are more susceptible to winter injury.
Deciduous Trees. February through March is generally regarded as the best time to prune most deciduous trees. Apr 23, When pruning mature, overgrown shrubs, remove the thickest branches first. Cut them back to the base of the shrub to promote new growth. Hand pruners are useful for smaller branches. Estimated Reading Time: 3 mins. May 24, Pruning actually stimulates growth. Pruning and thinning shrubs reduces disease pressure (examples - Macrophoma and Volutella leaf spot of boxwood and black spot of roses) by increasing air circulation and allowing foliage to dry faster.
Old overgrown shrubs can be renewal pruned to improve their appearance and reduce their size.