I have found this to be a good cultivar of the rhizomatous perennial groundcover Ajuga - other ones I have tried have tended to rot away in summer in my Sydney garden. It was apparently a mutation that occurred in tissue-cultured plants of Ajuga reptans 'Braunherz'.
It grows about 15cm tall and has glossy, large, dark blackish-purple scalloped leaves and deep blue flowers in spikes from early spring to early summer. It spreads by runners. It can grow in full sun or light shade, but the leaf colour will be darker in a sunny spot. If grown in sun, it needs more water than if grown in shade. It lends itself to contrasts with other foliage - I pair it with silvery plants such as Plectranthus argentatus in my 'black and white border'. I have also grown Viola tricolor 'Bowles' Black' in amongst it, and enjoyed the colour echo it created.
Ajuga species are regarded as useful bee- and butterfly-attracting plants.