Mexican Feather Grass Still Green Post-First Frost - November 2022 - Zone 5b

I planted an ornamental grass in one of our back patio containers this Summer and seems that I failed to document what the variety was/is when I installed the rest of the flowers.  Here's a link to a Summertime post showing the labels from a bunch of the plants in the containers, but it didn't include the ornamental grass in the center of the large, round ceramic container.  Based on poking around online, I'm *pretty sure* that it is a Mexican Feather Grass - Nassella.  

I'm posting about it, not just to document it in the [garden diary], but rather because of the state it is currently in - post frost in late November.  See below for a photo of the container including this Mexican Feather Grass still showing a lot of green blades:

Nassella Mexican Feather Grass is hardy down to just Zone 7, so perhaps I'm wrong with the identification.  Listen...everything else.  Literally EVERYTHING ELSE in my garden (aside from the Autumn Ferns) have shriveled up and reacted to the sub-freezing temperatures that we've had for the past week.  But this grass?  Doing just fine. 

The grass is/was kinda wild, but I liked how it held up and didn't wilt from the sun and lack of water.  Will I use it again?  Probably not, but never say never, right?