Take, for example, Salvia x guaranitica "Black and Blue," anise-scented sage. Imagine deep sapphire blue tubular flowers surrounded by black calyxes on black stems held above deep green anise-scented ...

There's something about black flowers that lend an air of intrigue to a garden, and yet they occur rarely in nature. Perhaps that's why they're an object of fascination for those who cultivate them.