I don't think you're much different than my location temp wise. Frequent snowcover will help it as well.I'd probably be more worried about zoysia in a frost/torch pocket like CON than up where I am.You could buy a sheet or two of plugs and just let them go. I will say my plugs in the back that I planted in loosened, bare soil took off a lot faster than the ones that I planted in the hard pack front that was already full of grass and weeds.