I love goat weed from the perspective of a native plant enthusiast! I actually had to google the common name to figure out you were referring to Croton capitatus. I'm partial to C. punctatus, a dune version of this genus.
As for Pinterest and copyright: I was an early Pinterest adopter back in 2011 when you had to get on a waiting list to be invited on. When an artist I follow, Kal Barteski, began having copyright issues with her work (she was using Pinterest too) that's when I left the site and closed my account. There's plenty of information regarding the copyright issues surrounding Pinterest and instances just like you had Dave...photos not linking back to you or crediting you, people taking their own liberties with them, etc. And in some cases, photos and artwork being used commercially because "I found it on the internet and isn't it public domain?" Not that Pinterest isn't the only place for this to happen, but there's been an explosion of copyright issues coming from the site.
