We planted non-native, non-invasive water lillies, - pink, red, yellow, and white. They bloom beautifully and spread slowly. I work them into the mud and placed a brick on each tuber. I just pulled up pieces of these to put in a newly constructed wetland this past week. I do not subscribe to the religion of only planting natives. As essup mentions, the two native species are invasive. For an authoratative discussion of natives vs. exotics see the June issue of Nature (page 153 under Conservation; Don't Judge Species on Their Origins, by Davis et al.). It points out that strict adherance to planting natives for conservation purposes is misguided.