Butterbur is the common name, did the sign indicate which hybrid? Very interesting plant.

I just yanked out some in my back yard (I don't know if it was a hybrid or which one, either, though). It's still sprouting from the root, so if you want to come get some, contact me offline (sooner rather than later). I'd be happy to trade for some rue or ginger.

I have Butterbur, too. Got it from Lynn last year at a swap. Glad to share if you want some.

Linda