Ajuga (Bugleweed) has been a favorite of mine throughout my years in horticulture.
It is a good ground cover as most varieties spread rapidly and even provide evergreen winter color.
As we have previously mentioned elsewhere in regards to other varieties should you live in the south you may find it advisable to provide a little protection from full sun locations.
I have observed these plants afflicted with winter burned foliage especially when established on berms and fully exposed to the north.
Cold dry winter winds combined with sun when planted as mentioned above can cause unsightliness with this ground cover.
For optimum results plant in full sun to partial shade and make your selections from the following choices.