Russian sage, known botanically as Perovskia atriplicifolia, is a flowering perennial sub-shrub that throws spires of lavender to blue flowers in the summer and fall. Happily thriving in less than ideal soil conditions and climates, Russian sage is hardy in USDA zones 5 through 9 and requires very little maintenance for performance save light watering and occasional pruning for shape and size. As a woody flowering perennial, Russian sage can be propagated by cuttings as well as by seed.
Collect Russian sage seeds from the desiccating seed heads at the end of the bloom cycle. Pluck or cut off the seed heads intact holding them over a piece of paper or flexible surface and funnel into a resealable plastic bag or other small airtight container until planting. Fill nursery pots or trays will fresh potting soil burying the seeds one inch deep and watering in well.
Harvest soft wood cuttings from your Russian sage in the late spring or early summer with a clean garden knife or secateurs. Make cuttings at least 5-inches in length and leave any foliage intact so that the cutting is not compromised in removing the leaves. Make a fresh cut on the bottom end if the woody cutting, immediately dip it in water and then into rooting hormone powder so that the bottom inch or so is coated. Quickly and carefully push the bottom end of the cutting into loose potting soil. Compact the soil lightly around the cutting to brace it and water in well.
Place your seed pots and cuttings in a brightly lit and humid environment that is protected from wind and from cold temperatures below 55 or 60 degrees. Keep the soil evenly moist to support germination checking on it daily as dry out, particularly for cutting can lead to a high failure rate. Pale whitish shoots should begin to emerge within a few weeks to signal successful germination.
Place the seedlings out into the garden when they reach a foot high or more. Spring sown seeds and summer prepared cuttings should have time to establish themselves and harden off before winter. If they are propagated later in the season the indoor housing period may need to be extended to avoid winter temperatures destroying the tender young plants.