You must use potting soil! And a good quality one at that. Garden soil, even amended garden soil, is too dense and does not provide sufficient drainage. In container gardening, drainage and aeration is key.

For woody plants that intend to be maintained long term in a container you need a very textural and durable potting soil. So no MiracleGro :-) Stuff like that is far too fine a texture and collapses too quickly, limiting drainage and reducing aeration..

I've attached a link to a long-running thread from the Container Gardening forum on growing trees in containers. The author - Al - is one of the most experienced and knowledgeable container gardeners around. Take everything he says as the gospel!! You will also find various recipes for quality potting soils on that forum, should you choose to make up your own. If purchasing, you want something that has a coarse, barky texture. Farfard (#52) and Metro Mix are a couple of names you could look for.

Here is a link that might be useful: Trees in Containers