Certified GKH Gardening Expert
Unfortunately, your photos did not come through. I am unable to see the damage.
Since you are at the lower end of where they can survive, I would expect winter damage to be a little more damaging to this grass. With this being said, any maintenance or pruning should be done in spring when you first notice new growth to avoid frost bite to the root zone.
Here is a collection of articles that will help you to care for the grass: