I'm not LeeAnne, but I have it in my pond and have seen it growing in the okefenokee swamp in south Georgia. It doesn't care how far it's submerged . . . it will grow with it's crown out of water or quite a ways under water.
Mine is in a large pot with just clay and it has a lot more roots than leaves, for sure. I keep the crown at the surface because I like it where I can see it and that's where the pot lands when I put it in that spot in my pond. When I got it, it was planted in a one gallon pot and I left it there for years . . . . when I finally transplanted it, there was no dirt left, just lots of roots. So I moved it to a big (5 gallon?) pot with lots of clay. As soon as I did that, the top spread and it got much bigger leaves. It also doesn't seem to much care if it's in sun or shade, tho I did see more of them in somewhat shady areas of the swamp than in the full sun areas.