Wish I had a good answer for you. I couldn't even find it listed in Taylor's Guide to Bulbs. In The Gardeners Guide to Growing Lilies it talks about it having having a stoloniferous growth habit. It gives no zone info, Go figure. "Except in favoured areas, it is a plant for the cool greenhouse where it will need growing in a border or large container to allow space for the stloniferous stems to wander 8-24 in before breaking the surface." quote
Perhaps try going to the American Lily Society website. Maybe you can get an answer there.

Thank you hostalolic2. I will check out the ALS website. If I can't find anything there, I may just leave the bulb (I just ordered one) in a pot for the winter and bring it inside just to be safe and put it outside again in spring.

Charlotte

Nepalense will probably survive z5/6 if the bulb is kept dry over the winter. So many times, and especially with bulbous plants, moisture content in the winter will spell death or survival more than temperature. Assuming you plant it in the ground, make sure it has excellent drainage, and over the winter, cover it with a 3 foot circle of plastic (impervious to water) to keep the area dry. L. nepalense emerges very late in the spring. Don't give up on it.

Thanks leftwood. I really appreciate your advice. I wouldn't have thought of using the plastic. Sounds like a great idea.

Charlotte

Charlotte, Dan Hinkley (of the former Heronswood) guesstimates hardy to Z5. Growing it in Z8 maritime I can't advise you on the hardiness but I wouldn't plan on lifting the bulb - this one is a runner and travels around your bed...sending up blooming stems in some surprising places. Two years ago I dug and replanted the area in which it is growing and found bulbs every which way :)

Mine has been dependable in clay based soil that is saturated all winter every winter. It's on the W side of my house so gets the 'benefit' of all the weather off the ocean and that means wet, wet, wet here.

Thanks, morz8. That is certainly important to know. I will definitely take that into consideration when I plant it and will plan on it staying in that spot permanently. I really appreciate all the great info. All of the responses have been really helpful. It will be interesting to see where new lilies pop up.

Charlotte