This grass amazes me. It is a zone 6 (we are a solid zone 5), and it comes back year after year and gets HUGE- reaching over 6' (it's only supposed to get 5')! It must love the spot it's in. I give it a 16-16-16 fertilizer a few times per season along with everything else, other than that it gets no special treatment. Because it gets so big, I usually have to fashion some sort of staking system around it to keep it from falling over late in the season. It is such a full grass, though, that you usually can't see the stakes.
I wish I had such great luck with everything else I planted!