I mixed this ajuga and mazus together last summer to fill in and cover the boring mulch around these rocks & stepping stones. I did not realize they would bloom & compliment each other so nicely this spring. The ajuga has deep purple spikes and the mazus is lower with more lavender flowers.
I rescued the ajuga from my neighbor who had let it get out of control in their lawn and was mowing it down every week. The mazus is quite the spreader -- I bought 1 container a few years back and have been spreading it around ever since and still have plenty to share.