11/20/2011 9:11 PM
Latitude 39 48' 6" is Springfield Il which is about as far north as I know in our area and that pretty much runs through St Joes, Little north of indy, between Columbus/Cincy, DC and a little north of there.
Dominant turf fwys/tees in St. Louis is Zoysia and we have a winter kill event about every 10 years or so with zoysia but not major.
10-15 below is about the coldest it can stand. Zone 6a is pretty good, 5b is pushing it but it will grow.
Meyer is still the best for cold hardiness but I know they have been closing in on other varities that might be getting close to its ability to withstand the cold.