I have done it by a couple of methods. First year I just dug a hole deep enough to cover the large tree pots about 6 inches. I dug the EE and shook the dirt off and put as many in the pots as I could and then buried them. I have also put the EE in pots but dug a hole about a foot deep and put straw bales around the hole. I put the pots of EE in the hole and covered with leaves to the top of the straw bales. In the spring just dig the pots out and replant. Do not put dirt in the pots just the bulbs.
Hope this clears it up a bit.

That is a good idea if I could dig a hole that deep in my rocks. The hay bales around a foot deep hole and leaves in the center might be something I will do - kind of like lasagna gardening. It could be a place to winter plants then a new planting spot next summer.

My husband has been digging a large, deep hole (when we take out the banana trees) and dropping a large tree container with good drainage down in it. Then he throws all the ee in, topping them with dirt. They are buried an average of 2' underground. Beerhog's methods work well for him, too. If I didn't have a spot to dig 2' down, I'd go with his idea. Main thing is to keep them from freezing..so depth will depend on frostline.