tough pic.. but i think it is what is called a fairy ring ... well.. i know its called FR ... the pic just makes it hard to be sure ...

the center has died ...

if you sharpen a shovel.. and can actually get it in the clump.. you could probably dig out the dead center .. and just throw some fresh soil in the middle.. and it will fill it in ...

if you cant.. dig it up.. and take an axe to it.. [some of these grasses require effort] .... and make a bunch of new small clumps ... and try to figure out what to do with all them ... lol ...

there is no need to buy more.. i suspect you will end up with 10 more than you need.. if you do the latter ...

i would not worry about disease or some such ... its a clump age thing.. along with perhaps drought ... or watering issues .... it is very common with older hosta clumps ...

ken

what in the world takes 15 minutes to explain .... . is beyond me.. lol ... https://duckduckgo.com/?q=Miscanthus+grass+clump+renovation&t=ffcm&iax=videos&ia=videos

Thanks all for the great tips.

And let me tell you, it's a JOB. My garden assistant and I--both in our 70s--managed to get some of my long overdue M. 'Morning Light' out, then had to find a strong young man to do the rest. The replant is doing well.

I had some like this, but not as bad as yours. My ring was alot smaller. Take a shovel and take pieces of it starting from one end, You could make like 5-6 small plants out of this clump, They grow fast and will be big again in 1-2 seasons. It a great dividing plant. I have over 30 of these now(started with only 2 5-6 yrs ago ). This is one of my favorite ornamental grasses along with the pink mulhy grass

Just finished dividing; what a chore!!! Like a hair transplant. Is Muhly grass hardy in southern Maine 5ab

I dont think so, I think tennesee is the furthest north you can grow it.

Muhly won't make it through a zone 6 A winter.

No it does not.