I've never seen instructions, from any resource, which calls for planting Muhly deeply.

As a matter of course, however, I always plant nursery grasses at the same level they are in their pots, particularly if it's obvious they have been in the pot for a while, and are doing well. When you pull them out of their pots, if they have a root mass which fills the pot well, and looks vigorous, go ahead and plant them at the same depth.

I just divided mine for the first time and I am afraid I did not plant them deep enough,their not looking to good compared to the ones that was yust a little deeper;Hightider