Hello,

Ornamental grasses can be cut back in the spring or the fall. Often people plant ornamental grasses because they provide all season interest. Even though they have turned brown and gone dormant in the fall, their seed heads provide interest in the garden during the winter. And they provide habitat for some native insects. Read more here: https://www.canr.msu.edu/news/maintaining-a-grasses-and-sedges-garden

And here: https://www.gardenatoz.com/what's-up!/main-features-this-season/fall-cuts-are-optional/

Thank you for contacting Ask Extension.