Well I'm surprised no one has replied yet. I have several oriental lilies in the yard and all do very well. If they are potted just plant them in well drained soil and keep watered until they get established. They will die back but reemerge next spring. I've also bought dormant bulbs and planted them in the fall. Many people transplant potted Easter lilies into the garden. I plan to buy some more at WalMart (on sale) and get them into the ground today.
Oriental lilies are real hardy plants and multiply, giving you more blooms each year.
Hamp

Mine are in large containers, and are doing very well. I keep them close to the door when they're in bloom!

thanks for all the info. I was given this plant as a gift for Easter and have never dealt with them before. I love the way this plant looks and it smells great. I would really love to keep this one alive.