I can't remember its name right at the moment, but when my mother-in-law's yard was completely redone last August (2007), many of these were planted. They're low-water plants and of not-so-messy habit.
They don't seem to spread very rapidly.
I do her yard work (maintenance only, not the landscaping) and haven't noticed these spreading, even after one winter.
Will monitor them for a couple of seasons for invasiveness...but so far, so good!
USDA Zone 9, Sunset Zone 17