I have a mature clump of zebra grass.

I cut back the dead leaves in spring.

A few weeks ago the new growth, now at full height, is all laying on the ground. I figured some wind knocked it down, but I think at least part of the clump does this every year. It is not overwatered/underwatered.

I've had this plant many years. Perhaps it is just past it's prime? I've already divided it once - extremely difficult and I wouldn't be able to do it again.

Would cutting it back be advisable?