Russian sage, also known as Perovskia atriplicifolia, is a perennial plant with silvery foliage and purple-to-blue flowers that bloom from July to September. It grows best in full sun with well-drained soil and reaches heights of about 3 feet. Russian sage is hardy through U.S. Department of Agriculture zones 5 to 9. It is extremely drought tolerant and grows poorly in wet soils, according to Russian sage is considered a form of shrub and needs to be pruned like one, according to Fine Gardening magazine online. Because it is a late-blooming herbaceous shrub, or "subshrub," Fine Gardening advises trimming Russian sage in the early spring before new growth appears.
Remove any dead, damaged or diseased foliage from the Russian sage with the the pruners at the base of the plant. Most of the die back will be on the tips of the foliage. Scissors can be used to prune near the tips of the plant.
Prune all of the Russian sage back to about 8 inches from the ground. This encourages new growth from healthy leaf nodes.
Shape your Russian sage into the form you desire by cutting back any over-reaching foliage. This is only necessary if your Russian sage does not experience die-back in the winter.
Deadhead the Russian sage in the fall after the flowers have faded. Leave any further trimming until the following spring.