Hello, I hope you’re doing well. I’ve had this grass growing in a moist, shady area along a northeast facing wall for a few years now. It’s spread very quickly, and seems quite aggressive. I don’t mind it being there for now, as I don’t have much growing there, but I’d like to know whether it’s native or invasive. If it’s native, I’m happy to let it grow, but I don’t want to keep it if it’s an introduced species. It usually grows to between 2 and 4 feet tall, and has thick, strong stems. It mainly spreads through underground rhizomes, and forms dense clumps. I don’t have any pictures of the seeds, but I did get some closeups of the stems. I can take more pictures if needed. Thank you!