Salvia guaranitica ‘Black and Blue’ (anise-scented sage) is a hummingbird magnet, hardy zones 8-10 and worth growing as an annual elsewhere. Both bees and butterflies abound when Salvia guaranitica is in bloom…the bloom period is very long for a perennial…June to frost. Can be a little aggressive once established, but not too much of a bother.
Dark colors (blue especially) tend to recede into the garden, so my experience is that Salvia guaranitica is best viewed up close; viewed at a distance Salvia guaranitica tends to show as a very healthy wall of green.
Also known as anise-scented sage, Salvia guaranitica thrives in full-sun to partial shade, flowering better the more sun available. Not particularly choosy of soil types, although plunking it down in stingy hardpan will do no favors…good, solid garden loam is preferred. Leaves are pleasantly spicy when rubbed between the fingers.