It depends on the size of the bulbs you receive. Larger bulbs should be planted on the deeper end of the planting depth range. Over time trumpet lily bulbs will get quite large. I dug and divided some today that had reached softball size. If you don't want to have to divide them for quite awhile space them in the 12-18 inch apart range. You would probably be fine planting them with about 6 inches of soil over the top of the bulb. Work the soil well in the hole and work in plenty of compost. Make sure the soil under the bulb is loose. Lilies have contractile roots and will pull themselves deeper into the soil as they grow. Enjoy your trumpet lilies.

Thank you! Now I'm ready.

And when you've finished planting, water in real good once to get trapped air out of the soil and to insure the best possible soil/bulb contact. Don't worry if bulbs don't sit exactly straight--they'll right themselves. And don't fertilize now. Next year when plants are 6 to 8 inches high you could add just a little of tomato or rose fertilizer around the outside very sparingly. Also, lily bulbs and feeder roots don't like baking hot bare soil so if thats the case, add an inch or two of wood chips to keep them cool and conserve moisture. Trumpet lilies are my favorite of all the lily divisions. They are more desease resistant and slower to multiply than most making them carefree and low maintainance; you'll really like them!

Actually trumpet lilies are the most vulnerable to spring frosts once they've begun to grow above the soil. So they need extra attention and protection.The slightest frost will 'cook' them. That's why I don't grow them anymore.