Not sure...but I have divisions of my first lilies bought 10 summers ago.

My waterlilies (in zone 5-6, hardy, pink, white) have lived about over 15 years, maybe even 20. They were divided, when planted (some leaves) but now, the "bush's" diameter is about 3m.

Denis

I think they could probably live forever, if you keep dividing them. If you don't, they will get so cramped in your container that they will die. And don't forget to fertilize them at least once a month!

To maintain vigor the roots should be divided when they get to be fairly large. What Catherine said is true for many perennials.

Many of the classic hybrid plants that Marliac pioneered over a century ago are still going strong and keep going after being divided over and over again...

thanks guys:)

My family has had a water lly in the family for 94 years, with multiple cuttings spread around. It was originally taken as a cutting by my grandfather from a fountain in the town square of Magdalena, Sonora, Mexico in 1923. How it got there is anyone's guess. Hard to imagine they can live forever, but pretty clearly they can last a long time.