What are the differences between container, B&B, and bare root trees?
After you have selected the right tree for your planting location, next you must decide what kind of tree to get. The three main nursery root stalks available are container, ball and burlap (B&B) and bare root.
Container trees are grown in containers. Be sure to get these from a reputable dealer. Roots must be shaved with every up-potting event to reduce the formation of circling/girdling roots. When planting, the hole must be deep enough to ensure the root flare is a few inches above ground level and twice had wide as the container. Check the root ball for circling/girdling roots once it is removed from the container. Loosen circling roots and pull them straighter when possible. Cut them when this is not possible. Tightly backfill to hold the tree in place.
B&B trees are grown in the field. A large machine cuts the roots before the root ball is wrapped in burlap and placed in a basket. The basket may not always be used. The size of the root ball depends on the caliper of the tree. See a graph of these sizes here.
When you receive the tree, move the trunk to see if the tree is loose in the root ball. There should be no movement of the trunk independent of the roots. Independent root/trunk movement can mean that the root structure is likely compromised. Use a different tree.
Dig a planting hole twice as large as the root ball. Ensure the depth allows the root flare to be a few inches above ground level. Remove the top third to half of the burlap and basket once the root ball is in place in the planting hole. Tightly backfill to hold the tree in place.
Bare Root trees come in a variety of sizes. After carefully removing the tree roots from any packing materials, soak the roots for 2-3 hours. Dig a hole twice as large as the root area. This hole will not be as deep as a container or B&B trees. When placing the tree in the hole, ensure the root flair is a few inches above ground level. Tightly backfill to hold the tree in place. Bare root trees are best to plant in the spring before they begin to leaf out.
Why should the root flair be a few inches above ground level? As the tree settles the root flair will drop. Keeping it a few inches above ground level at planting ensures it does not go too deep after settling.
Read more about planting and establishing trees here