It looks like one of the narrow-bladed Miscanthus sinensis cultivars, possibly 'Gracillimus,' or 'Graziella.'

thank you. My guess was Gracillimus!

Looks like 'Gracillimus' to me also. I have a couple of these in a fairly narrow bed between the driveway and the house that someone planted before I moved in back in 2001. They've performed well although they usually get all smashed down by snow (most of it shoveled on top of them by me) by late January. I cut them down after this when I have a chance, and several times I have cut out part of them in spring to try and keep them from overgrowing the space.

This year, however, I am taking them out completely. I plan to replace one with P. virgatum 'Northwind', which I think will fit the space better. The other one is definitely in too narrow a spot, probably will go with a swath of columbine or some other native perennial there.