how old was the lily? was it growing in your pond last year? What zone are
youin?

I would give it a few more weeks. If it hasn't shown new leaves when the water
temps have been 60 for a week I would pitch it. Some types of lilies are prone
to crown rot. I would make sure if the crown is slimy and it doesn't come
back....Throw out the pot, and the soil. Buy a lily from a different store,
and a different type of lily. Place it in a different part of your pond. If
you know the name of the lily , tell me and I will look it up for you Jerri

http://www.fringeweb.com/Ponds/JerrisPond