I'm not sure what grass you're talking about, but there are several things that could effect it. I know there's a weird pocket somewhere between W/S and K-ville that seems to be abt a 7b instead of 7a. Good soil drainage helps,... Placement could make a difference. Near a south facing wall or drive could help it. I think the biggie though will be just what kind of winter we have. The last few have been mild, last one super mild! If we get a cold one I think some of the things I've been surprised that made it through winter are going to be in serious trouble, especially my borderline tropicals.

Have you looked into maybe saving seed if it's not sterile? That's what I use to do with my bunny tail grass.