Frosted Jade Ajuga. This choice selection has fantastic foliage and very good dark cobalt flowers.  Not a spreader - this makes a clump with 16" tall stems.  Challenges all of your comfy notions about Ajuga but in a good way.  Great in our shade garden.

Rare plant found only in limited areas in central Honshu, Japan where it likes the forest fringes in the subalpine areas and is known as hiiragi-sou or holly tree-leafed weed.  Hiiragi-sou sounds better than the translation.  This selection has dark blue flowers and is a deciduous clumper to 16" tall - very nice!