Definitely no spinach or beets. As much as I'd love to grow datura, poisonous plants scare me. I already come up with new spots every time I'm out there, and as there's loads of plants that could be skin irritants, I have no way of knowing which cause what, so I'm not going anywhere near datura. I was scared to touch the milkweed and sunset flower last year!
As for the lilies, I cut two right back last year on
trashpony's advice. The stripey one survived, and I'm pretty sure I binned the other one because it didn't look like it was going to grow back, so I don't think it's that.
What about the tall one in the hanging basket? (post 529)