Totally agree about the ajuga—it’s relentless. I tried it once thinking it'd be a nice filler around stepping stones, but within a year it was everywhere. Lesson learned. Also, dwarf mondo grass is solid, but I've noticed it can look patchy in shade-heavy spots. For shaded areas, I've had better luck mixing in creeping thyme or Corsican mint—smells great underfoot too, bonus points there.
I had a similar experience with ajuga—thought it would be manageable, but it quickly became invasive and difficult to control. Creeping thyme has been a reliable alternative for me as well, particularly in shaded areas. One thing I'd add is that Irish moss can also work nicely between stepping stones. It stays relatively compact, tolerates shade decently, and gives a clean, tidy appearance without spreading aggressively. Worth considering if you're looking for another option.
