Stimulating growth by pruning can also interfere with the plant going into winter dormancy which can make it more likely to be damaged by cold. Cold damage can cause branch die-back, basal cankers and even death.
Don’t prune spring flowering shrubs (azaleas, dogwoods, forsythia, etc) in the fall. These plants have already set buds so you would be cutting off next springs flowers. As a general rule, plants that flower BEFORE July 1 should be pruned AFTER flowering. Plant that bloom AFTER July 1 should be pruned in late winter or early spring.
Trees and other herbaceous plants may be best pruned in late winter or early spring while the plants are dormant and before buds begin to swell and open. Do not prune when temperatures are below 20 F.
For more information see the UT Publication “Best Management Practices for Pruning Landscape Trees, Shrubs and Ground Covers" here: UTPB1619.
Blog by: Linda Lindquist, CMG