I think the reason the rosenverig looks so sad is they're not emersed plants.
Any more, I'm of the opinion if a cordata form (and goodness knows, there's dozens if not hundreds of different ones) is over two feet long then it's part of a morphospecies gorup that had adapted to deep water. Not all cordata forms can grow two feet or more in height so the branch of that family adapted to fill a need for getting light by sending up tall stems. That didn't happen overnight and there would never been a need to do this if the plant grew emersed. So, I think the diant cordata forms sould be considered submersed only, and luckily they do well in any water soft or hard, thrive well and throw lots of runners.
The cordata forms you see doing well in emersed culture probably came from a river bank.
The giant ones live *in* the rivers.
(24" tall tank)
The weight of the leaf is more than that long long stem can handle, and they always look droopy in emersed culture.
Unless you stunt them: