Forsythia shrubs bloom in the spring, and their flower buds have already been set for next year. So we do not want to do any pruning right now. We ideally want to prune within two weeks after the flowers have fallen off. And once your forsythia shrubs are established, you want to prune a third of the thick woody stems all the way down to the base. Forsythias flower on the thin young stems so pruning the thick wood out, is going to allow sunlight to get into the center of the plant and allow for