I think you can get away with hardy water lilies as the seasonal cold will make them dormant and check thier growth somewhat. There are dozens of varieties, I myself grow over 12. Mostly minitures. Keep away from tropicals as they will just die in the winter.
If you insist on cattails, and I would be careful there, try graceful and or mini. They are much more ornamental. Easier to control and take care of.
I really like rushes. Cape, corkscrew, horsetail and striped, maybe even zebra if they can tolerate the cold. There are many other already mentioned choices in this thread that are great.
I think, or to me I have three questions I ask myself on everyone of these projects.
Do I want permenant plants or just this season?
If I put them in will they take over, can I remove them?
What is my intent?
This is something I do quite often. I guess aquatic landscaping and control is my number one business. Looks like a nice pond.
