I'd never heard of this before a couple weeks ago, though we'd had it since spring. I just never noticed. Davesgarden.com says that it blooms a couple times, in early summer and late summer, but I never noticed it doing anything in early summer, and surely I would have paid attention to something like this, right? I mean, it's very yellow.
I'm also amused that it's named "Trollius." If I ever have to put comment moderation back up due to trolling (I did a couple weeks ago, briefly, because an unstable Christian troll from Australia wanted to spam the comments, but he appears to have been distracted by something already.), I'll have to signal the change by posting this picture again. Like when they fly the black and red Hurricane Warning flags.