Kate,
Sounds like it's natural thing to do at this time of year....
As soon as it flowers, and the flowers start to decline, cut the flowers off *so no seeds form~that saps the energy away from the "bulb" to make more green and more flower for next year*

But let the plant die back naturally and when it's finaly brown all the way down to the bottom, then cut it off, They go thru our winters here in hybernation, and in spring, come back thru the dirt and in time will flower again...
Just don't cut off the green stem before it dies, that's how it feeds it's self to put all that energy back into the bulb for next season.....

Keep us posted on how your lilies turn out!!!
We LOVE updates !!!!

Weezie

Waht growing zone are you in? Do you know?

P/S Welcome to The Garden Helper's Forum by the way, we are very glad you found us!!!
You'll have lot's of fun here!

* * * *
Weezie

Don't forget to be kind to strangers. For some who have
done this have entertained angels without realizing it.
- Bible - Hebrews 13:2





http://photobucket.com/albums/y250/weezie13/

The only other thing I could also think of
is your planting method???
How deep did you plant the bulb in the tub?
They do have to be planted a few inches down to grow up properly, but sometimes if it's planted way too deep, it expends all it's energy to get to the surface and then only has enough energy to grow the green stem...
If it got enough food and water over the summer, it should be able to produce a nice flower *I'm hopin'* next year.

And how big was the bulb the first year you planted it?
Sometimes if the bulb was a smaller bulb when first planted, it will then again, only produce a green stem...You're always better off to start with a good sized bulb.. Not always, but a good rule of thumb...

Or Voles, they also love to eat those bulbs *tulips too*, if they naw on it, eating some of it, which can cause only the plant to grow green stem and not much more.

Some other ideas to keep watch for!!!

Weezie

* * * *
Weezie

Don't forget to be kind to strangers. For some who have
done this have entertained angels without realizing it.
- Bible - Hebrews 13:2





http://photobucket.com/albums/y250/weezie13/