Yes, too late. What you describe is a warm season grass and they should not be planted after early fall, let alone divided or a hunk dug up and relocated elsewhere. Warm season grasses have a root system that only responds to warm soil temperatures so as the soil cools down in fall, the roots stop growing. Planting or transplanting now just results in inactive roots unable to re-establish in cold, wet or possibly even frozen soil and the plant will very likely die. Or at least the disturbed portion.

Wait until spring and the soil warms and you start to see some new growth appearing before you divide or transplant. And if you have never undertaken to divide or transplant an established clump of ornamental grass, be prepared - they have a very dense, congested and heavy root system and it's a heck of a lot of work and hard labor!!

Thanks so much for the great advice!