Russian sage (Perovskia atriplicifolia) is a perennial sub-shrub commonly grown for its spires of flowers, silvery leaves and relative ease of growth. The plant grows in a small, compact habit and reaches 3 to 5 feet in height with a 2- to 4-foot spread. Russian sage flowers during spring and summer, producing numerous stalks of light blue flowers. Both the stems and foliage produce a powerful aroma when crushed, though the scent is not considered fragrant. Native to the Middle East, Russian sage thrives in hardiness zones 5 through 9 and makes an ideal mass planting or addition to mixed borders throughout the United States.
Plant Russian sage during mid-spring after all danger of frost has passed. Select a planting location that receives full sunlight throughout the day and consists of well-drained, moist, fertile soil. Space Russian sage plants at least 3 to 4 feet apart.
Spread a 1- to 2-inch layer of mulch over the soil around Russian sage to provide insulation, improve moisture retention, and stunt weeds. Do not allow the mulch to touch any portion of the plant, as this will increase the risk of disease. For the best results, allow several inches of space between the mulch and the base of the plant.
Water Russian sage once every week during spring, summer and fall to keep the roots from drying out completely. Reduce watering frequency during winter to once every two weeks in zones 7 through 9. Do not water during the winter in zones above 7. Soak the soil to a depth of 4 to 6 inches at each application to provide adequate moisture.
Feed plants once per year during late spring using a slow-release fertilizer to gradually release nutrients into the soil throughout the growing season. Water lightly after applying to dissolve the fertilizer granules and prevent injuring the plant's roots. Apply according to the manufacturer's directions for the best results.
Prune Russian sage during late winter, just before active growth resumes in spring. Use pruning shears to cut all stems to the ground, which rejuvenates the plant and encourages new growth.