If you want slow growth in more of the shallow water then buy the dwarf and small varieties of hardy lilies. The Medium and Large varieties grow in deeper water 7-9ft and spread faster esp the larger white and yellow varieties. In ponds, I highly suggest not using the wild species of water lilies because the grow deep and their seeds are fertile and rhizomes fragment both allow fast spreading. Soft sediments allow for faster spreading.
Thanks for the information. I have a decent size grass carp in this pond. Is he going to be hard on new plants?
