How to prune salvia verticillata 'purple rain'

After each bloom flush in summer; hard cutback in late autumn to early spring. Trim spent flower stems back by one-third to one-half after each flush. In late autumn, cut the entire plant to 3–5 inches above the crown once frosts have finished it off.

Two times per season; annual hard cutback. Salvia verticillata 'Purple Rain' produces whorled lavender-purple spikes and reblooms if deadheaded or lightly sheared after each flush fades. It is somewhat more sprawling than S. nemorosa types, so a firmer mid-season cut helps maintain compact habit. Cut back hard to the base in late autumn or early spring.

Trim spent flower stems back by one-third to one-half after each flush. In late autumn, cut the entire plant to 3–5 inches above the crown once frosts have finished it off.