Meyer; thanks for the link. I followed a couple of leads though, and there's no zone hardiness, which is what I'm most concerned about. That's why when I read the plant typically exists in southern countries/states, I have to figure my chances of growing/keeping alive in a pond, go down. I figured that if I can't get the oxygenators via usual online resources, probably there's a reason. Like you said; I don't want to replace them every year. I do like the idea of plant diversity both above and below the surface, but if conditions aren't conducive, I'll make do with what I can grow/control. There's more than enough variety as I've already shown. I just liked the idea of adding different plants. I may try some cabomba or vallisneria, but not until I have enough grown in an aquarium to withstand grazing/water conditions.
Nate; I think as you build your pond, keep this whole idea in mind re aquascaping, but realize you're more southerly and should have more success (than me). Still, try some that are NOT as hardy in your zone and see what happens. I think then you'll know what I'm up against. You can control all the variables in an aquarium (interior) but outside, I'm at Nature's whim. Many, many floating and marginals that I can use and I have. And the floaters reproduce so fast, and are very inexpensive to replace each year, that it makes a lot of sense for me to 'scape' the surface and not worry as much about beneath.
Michael