Hardy hybrid varieties are fairly reliable on large ponds and lakes, take care to plant them where they are easy to paddle and crop every couple of years, they may spread at the rate of a foot or two a year when they have settled in.
Establishing waterlilies may need protection from the likes of turtles, ducks and large carp trying to graze on their brittle and tasty feeder roots
Below is a piccy of a strong growing 'marliacea carnea' barely coping with pressure from grazing swans and ducks, who find the young foliage and roots of lilies quite an attraction early in the year
http://community.webshots.com/photo/99477855/97297215IttXdj Waterlilies provide shade from hot sun, shelter for small fish, and a good feed for many critters that contribute to the food chain... Some folk even get them just for their good looks, lol
There arent so many varieties to be considered carefully of as posing an 'invasive' risk, native varieties that drop too much fertile seed, native lotus which can spread 20 feet per year, the nuphars which can swarm into deep water where they start up in deep water (though they are still easy to yank out with a hook on a pole)
When you see a lake smothered by lilies, it took many years to get into that state, there's a fair chance someone chose a poor variety of lily probably free or cheap, tied it to a brick, and threw it in deep water many many years ago.
When a drought comes along, or if the water levels are dropped, its fairly easy to slide a knife along the rhisome, and yank each rhisome out in a few seconds, while they may seem 'a big deal' to get at, if you can paddle among them, they are really quite easy to crop. Unless of course they were put into inaccessible depths...
Planting a well chosen variety in a suitable position is a different kettle of fish, altogether
Regards, andy
http://i93.photobucket.com/albums/l42/adavisus/
