The "Blue Queen" variety of violet sage grows 1½' tall in my garden.  It is supposed to bloom all summer, but mine only bloom for 3-4 weeks at most - even with deadheading.  Violet Sage is easy to grow from seed, but don't expect any flowers the first year like most sources claim.  It's foliage is aromatic, but rather unpleasant.  A few butterflies seem to like it.