How can I effectively prune Hydrangea arborescens to promote healthy growth and abundant flowering?

To effectively prune Hydrangea arborescens for healthy growth and abundant flowering, prune in late winter or early spring before new growth begins. Remove dead or weak branches at the base of the plant. Cut back one-third of the oldest stems to the ground to encourage new growth and more flowers. Avoid pruning too late in the season, as it can reduce flowering.