Bur oak is a very long-lived, hardy tree that also goes by the name mossycup oak. It can develop a massive taproot, as deep as 10 feet. The species does well in prairie habitats, as well as city environments. It is tolerant of drought and requires very little pruning or training. However, doing so can improve a bur oak's shape and health.
Prune bur oak trees during the dormant season only, which is between December and March. They should never be trimmed during the growing season because exposed tissue under the bark will cause insect infestation.
Keep pruning to a minimum in the first 2 years to allow the roots to become established. use shears to remove any shoots that are competing with the central leader or trunk of the tree.
Remove lateral branches that are growing upright instead of sideways in the second to fifth season of growth. Also cut off those that are too big; they should be less than half as thick as the central leader or trunk.
Use pole pruners to remove branches higher up in the tree's canopy. Look for those with V-shaped connections to other limbs, as opposed to stronger, U-shaped connections. This should be done when the bur oak is five to ten years old.
Trim off branches that grow on the bottom of the canopy and face downward. They are not getting the necessary sunlight and air circulation, and are not aesthetically appealing.
Cut broken, diseased or dead branches no matter the age of the bur oak. Trim them in the joint where they meet healthy limbs.