Did you know that proper shrub pruning can greatly reduce plant pest populations? Heading and thinning cuts are made in a way that allow air and light penetration into the interior of the plant. Air circulation is a critical factor in fighting disease in plants like boxwood. Pruning boxwood correctly is essential to the health of the plant.
Timing is also a critical factor. Late season pruning may stimulate growth that may not have a chance to harden off before winter. This can kill the branch.
One must know if a plant flowers on new or old wood. Making cuts at the wrong time of year can remove the following years flower buds. Plants like azalea and hydrangea flower on old wood. They should be pruned after flowering.
Plants like Abelia and Forsythia flower on new wood. They can can be pruned anytime except Fall.