Best time of year to prune/trim trees
Pruning can be done any time of year, but there are definitely BEST times, especially if there is a lot to be cut.
Deciduous trees that flower before the end of May should be pruned as soon as blooming is over.
Deciduous trees that flower after May should be pruned between Jan & Mar. Prune flowering cherries in late summer, flowering evergreens in May, conifers in autumn. Cut out dead, damaged, or diseased wood as it is discovered.