Chasmanthium does prefer shade and moist conditions, but I've got some growing in containers outside in full sun and they do fine with adequate watering.

They are a warm season grass and you are in zone 7, so it may just not have established itself well enough yet and if the grass receives more sun, it needs more water. My guess is that once established, you won't have to worry so much about watering as often. They are actually fairly drought tolerant for a woodland/stream lover, and an overall pretty tough grass.

Thanks grass guy! For the time being, I'll give it a little more water than the others.

A lot of container plants sold in nurseries are grown in pine bark mixtures that drain very quickly and don't hold a lot of moisture. Most growers have irrigation and water frequently, so the mixture works fine for them. Sounds like your plant could use some supplemental watering until it is established better. I've found that River Oats is pretty drought tolerant once established. I never water the ones in my yard, and rarely water the ones I've got in containers.

Thanks Dawgie! We just got some rain and I will keep a close eye on it to make sure it is getting enough water.