Cerinthe major purpurascens 'Blue Honeywort' or 'Blue Shrimp Plant' - Outstanding selection with grey green foliage and beautiful blue blooms. Easy to grow in full to part sun, great for bees and butterflies.
A new plant variety on the market is Lunaria annua 'Corfu Blue'. Despite its name, this honesty is at least semi-perennial. It is in full flower now (March and is really appreciated by the small tortoiseshell butterflies.