Cut sage foliage back to 4 to 6 inches from the ground in the spring when new growth appears. Make cuts at the base of the leaves where they join the main stem, or cut bluntly across the top of the entire plant. Remove any dead or decaying plant material from around the plant.
Cut sage back by 6 inches when growth reaches a height of 12 inches. Greg Stack, Extension Educator at the University of Illinois, explains that this causes the plant to grow with dense, compact foliage.
Cut sage back by several inches after blooming to encourage new growth.