I know the grasses can be a challenge to ID, but thought I'd give it a whirl. I photographed four variegated species over the weekend which were all approximately 12" or less in height and this is the first of them. All were on display at local public gardens so I presume they may be cultivars available in local nurseries in upstate NY area.

This particular grass was situated in partial shade (alongside what appeared to be wood ferns or NY ferns) as an understory planting in a fairly dry area and did not appear to be receiving any supplemental water.