Water lilies planted directly on pond bottom

Can I plant my water lilies directly on the pond bottom if I use soil and plant amongst rocks? I live in Québec so the pond freezes in winter.

Doug says you can actually plant the water lily among the rocks without soil and it will grow. And as long as your pond is deep enough to not freeze solid to the bottom (or you leave a pump running in the pond all winter to keep some of it from freezing) then your lilies should be fine.