When to prune for stems
Late winter (February) or early spring (March), before the leaves begin to appear on the stems, is traditionally considered the best time to prune. However, to allow the maximum time to enjoy colourful stems, shrubby Cornus and willows are now typically pruned from late March to mid-April, just as the new growth is developing.
Plant roots and shoots are in balance and, after hard pruning, plants will regrow to re-establish this balance. It is important to prune in the dormant season as the plant resources are largely in the roots and can be used for the required vigorous regrowth. If pruned in summer, plant resources - which, by this time, are predominantly found in the leaves - will be removed, and regrowth will be less strong.