At this point in the winter it would be difficult to say for 100% sure.
What I do believe is that it is one of the tall "Scirpus" species - some of which we refer to as bulrushes and others we refer to as grasses (i.e. wool grass, river bulrush, barber-pole bulrush, Northeastern bulrush, nodding bulrush, etc....). All of these have Latin names that begin with "Scirpus."
I've seen different ones of these pop up on my wetland areas, but have never seen any that were aggressive here. In the summer it usually isn't difficult to ID the exact species. I've also been told that there are some introduced species of this family that might become aggressive in perfect storm situations, but I don't know much about those. I would just observe, and next summer get a positive ID.
