© © wrote:

Well the rhizomes I bought from E-bay (just put in the water and watch
them grow) type did not sprout at all.

What did I do wrong ?

Can I save the rhizome and try again next year ?

Dig it up, wash it off and examine the tuber. If it's hard, it's still OK.
If it's mushy, it's dead or dieing. If it has a green crown on a solid
portion, you might be able to cut away mushy spots and save it - but there
are no guarantees on that!

How many growing (sprouting) crowns does it have (like the eyes of a
sprouting potato)? Odds are very good that it had _one_ when it was
planted, and that appears to have withered. There are probably one or more
others that haven't fully developed. If this is the case, you planted it
too deep. This is one of the reasons I advocate just tying a lily to a
rock and dropping it in the pond. The growing crown _must_ be above the
soil level. Otherwise, it will give up on that one and try to grow a new
one.
--
derek