Well, I knew it ate a lot of things, but that's a new one on me. I forgot they use Twinflower. I dug up some from my neighbor's yard years ago and planted it right up front to try to get it to spread like a groundcover. I also have Carolina Petunias and my (other) neighbor has Firecracker Fern. But I don't see Buckeyes too often. I've never found a caterpillar before, but I'll keep searching! Congrats on yours, Ann!
