Rain garden/ornamental grass
I am wondering about the species of this grass. It showed up on the edge of a rain garden. I believe it crept in from an adjacent ornamental planting of the same grass. I am wondering whether to pull it out of the rain garden in case it is aggressive and will outcompete the native species like switchgrass planted in there. The grass is in full sun, and is around 8 feet tall. It is setting seed starting to let go of its seed now, in mid-November.
This looks like miscanthus sinensis, also known as maiden grass or silver grass. This is not native and, in fact, has become invasive in Maryland. We'd recommend that you cut off the seed heads now, at least.
The plant can be dug up or it can be cut down and the clump base (only) sprayed with an herbicide containing glyphosate. Spraying must be done when the plant is green and actively growing in order for the herbicide to be absorbed. One application should suffice.