Answer: Semi-dwarf trees can reach heights of 5'-13' (depending upon rootstock), with an equal spread. Given the dimensions of your garden, I'd plant only two. This will provide each tree with plenty of air circulation and elbow room to discourage disease, and eliminate over-competition for sunlight and water.
Bare root trees and those grown in containers have equal ability to grow into healthy specimens. Usually bare root trees are a little less expensive than those growing in containers. Inspect the trunk and branches of the trees before you purchase them, looking for straight trunks and evenly spaced branches and avoiding trees with obvious injuries or branches protruding at odd angles.
Plant your new trees so they're at the same soil level as they were growing before, and be sure to water faithfully each week until the trees are well established in their new homes.
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