A little tweaking and it's the Deadly Poppy Field from the Wizard of Oz.
I love that this flavor naturally fits and gives reason for a white-green pairing. Love it like I do with Chained to the Rocks. I think, mechanically, this would be too annoying and strong. And bonus points of the revision means that every creature that attacks you could get affected by the card (they all cross the field - well, except flying creatures? Bleh. Too specific, perhaps).