Clump was about 3' across - maybe 8 or 9 years old? Noticed that it isn't coming up like the porcupine and the morning light miscanthus grass I have nearby. They are about 14" tall - the zebra was maybe 3 or 4"?
Went over to inspect the clump and while I was cleaning up some dead stuff - I pulled the ENTIRE clump (which is really only about 12" now) OUT OF THE GROUND with my hands!!!! Holy guacamole! I know how deep rooted these ornamental grasses are and was shocked when it lifted right out of the ground. Lost a tree peony in the same bed (very sad about that). My neighbor suggested voles, although I have no other evidence of it.
Anyone have this happen? I'm really bummed because it was one of my most favorite (and biggest) clumps and loved, loved, loved the flowers in the fall...it is still alive, but I think I'll have to put something else there - this will be much, much smaller then years past - it's really a center-of-attention spot right in the front of the house. Picture below.