Answer: Lilies need a location in full sun and with a well drained soil. Planting on a slight slope can help assure the drainage is good. Since it has been sheltered in a greenhouse until now, you would need to wait until the weather has settled and frost is over with before you plant it outside. In the meantime, keep it in a bright and cool location. It may be set outside on mild days and brought indoors at night to protect it from freezing. Keep the soil evenly moist but not sopping wet.
Although sometimes people are able to grow their Easter lilies, often it does not work out. Many of the lily varieties that are forced for Easter sales would not be winter hardy in Illinois. Also, since they are bred for greenhouse forcing they may not be good performers in the garden. If you would like some lilies in your garden you might want to check with your local nursery and look in their perennial department.
I hope this helps!
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