Why Prune in Late Winter or Early Spring?
In temperate regions, most plants go dormant during the winter. This is the time of year when they’ve halted active growth and have hunkered down for the cold weather. Because of this dormancy, late winter and early spring are typically the best times to make any adjustments to the shapes of many trees and shrubs. Why?
Pruning while a plant is dormant makes it easier for the plant to recover which is important for next year’s flowers.
By pruning BEFORE any new growth starts, the plant puts energy towards producing new, healthy growth when the warmer temperatures of spring roll around.
Practically speaking, it’s also a lot easier to see the true shape of deciduous plants in the winter, since their foliage is gone.