it only flowers the once, in the spring- you might get one or two flowers on new growth, but they're rare.

cutting them back by 1/3 to 1/2 seems to work best- so that the stems stand up on their own again.

I'm more interested in getting them to spread than I am concerned with the way they look, so when they get ratty in the center as they spread out, I make a 'part' there (you know, like hair?) and mulch it to encourage rooting. this year, I got to move some of those babies to another spot :)