Yellow Flag Iris

I found this yellow flag iris along the banks of the Watauga River in Elizabethton, TN. Although it's beautiful, in many states it's considered a nuisance and invasive plant (some go so far as to all it a "noxious weed"). It spreads along ditches, ponds and streams and creates thickets that crowd out native plants. I can see this beginning to happen in places along the Watauga. But a weed? That's just too harsh for something so alluring.

What is a weed? A plant whose virtues have never been discovered.
--Ralph Waldo Emerson