They’re some kind of wetlands vegetation, obviously.  They remind me a little of the “cat tails” that grew in a marshy section of the woods near my childhood home.  (Bizarrely enough, that was in central Long Island, where you kinda don’t expect to find wetlands.)

The stream below these stalked sentinels was teeming with quick minnows today, along with metallic blue dragonflies above them.  I wanted to explore it pretty badly, but the vegetation is so thick that it’s waist-high.  I was issued some pretty dire warnings upon my arrival in Virginia about poisonous snakes, especially near the water, and I take those warnings pretty seriously.