I suspect they're also quite tolerant in the heat; I let some seedlings bake to a crisp one summer and although I thought they were totally dead (pot was feather-light, leaves had gone past sunburned to a scary bleached white appearance) I put them in water about an inch deeper than the crown and in a few days they perked right back up.
In the wild they grow in seeps and streams, so I suspect as long as the water is aerated and changed regularly you could treat them like any other shallow-water/transitional pond plant.
PS - I guess the answer depends on what you think of as "drainage." The media should drain well - but the pots don't have to be kept out of the water. Contrary to the folks down at SNW, I use big, tall pots for my specimen plants, just so I can leave them in trays of water without having to worry about the roots getting too soggy. (Big pots are also a good provision against freezing and drying.) The ones in shorter pots don't seem to mind though.