A wise NW gardener once answered with “Whenever you have time!” There is a lot of truth in this tongue-in-cheek response. With our long growing season, if you intend to precisely time your efforts, you will soon fall behind. For deciduous plants two prunings usually works best. Summer pruning is especially helpful for out-of-control trees as it helps reduce the amount of energy the tree will store before dormancy. Winter pruning allows you to assess the tree’s overall structure and then shape it up. This two-step process eventually controls unsightly watersprouts, or “suckers” as they are commonly called.