I thought it was a horsetail, I'm not sure why

Horsetails, Equisetum, are primitive plants related to ferns. Scirpus, the
bulrushes, are in the sedge family. A careful examination should reveal some
clues. A field guide might be some help.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)