Russian sage
Perovskia atriplicifolia
Is drought tolerant, grows in zones 5-9, performs best in zones 6-8
2-5' tall and 2-3' wide
propagate through cuttings
Prune back to about 6" in the spring, before new growth starts,since the best flowering occurs on new growth. In warmer regions, deadheading may result in a second flush of bloom. Otherwise, leave the flowerheads for winter interest.
Information that I've read states that it grows well in poor rocky soil. I've observed-in poor soil it has a slower growth. It will take at least a few years to fill out, the stems become woody,with a woody crown. Will grow in partial shade but will become leggy and will need staking.
interesting readings on Folk medicine relation in regards of this plant
http://www.pakbs.org/pjbot/PDFs/42(...3)1465.pdf