Pampas grass will work up there but it can get really huge and messy. If you are only looking to screen give feet, big muhly might work or gulf muhly/pink muhly which is what is shown pictured a few posts above. Problem with the muhly grasses is they freeze almost all the way to the ground in the winter. They grow back quickly in the spring though.
All the grasses mentioned by Apache would probably work too. Apache knows his plants. Wax Myrtle is another viable option up there but it is not grassy. Very fast growing though. I like yaupon too as a border, but it too can get kinda wild if left to it's own devices without any pruning.
CM