Pruning your holly tree is important for more than just aesthetic reasons. Getting rid of all of the old growth will encourage new growth by making sure that the core of your holly tree receives proper sunlight and that it doesn't have to compete for space with limbs that have already perished. Pruning will also encourage the growth of new holly berries, which along with the shaping of the tree, will lead to a more beautiful landscape piece for you to enjoy.
Choose the right time to prune your holly tree. In general, the best time of year to do this is around the middle of December while the tree is dormant. This will give your holly tree the chance to make the most of its new growth for the year. Do not prune after flowering, as this will stunt the growth of the holly tree.
Put on protective gear. It is always important to don protective eye-wear and gloves before taking on any pruning project. In the case of holly trees, it is even more important as the leaves are stiff and have sharp edges which can cause injury if one is not careful.
Cut back small branches that have begun to grow within 4 feet of the ground. On occasion, holly trees will get small limb growth in this area and it is necessary to nip it in the bud. Pruning shears should be more than sufficient to the task.
Remove dead branches that have broken loose from the tree but have not fallen to the ground yet. This will allow you to get a better idea of the portions of the tree that actually need pruning.
Cut back branches that have begun to grow in a downward path below the lowest normal level of the tree canopy. Cut these branches off as near to the trunk as possible without actually cutting into the trunk of the tree.
Cut back branches that appear weak or spindly, branches that are crowding other branches, or ones that are growing into other branches. Begin at the bottom of the holly tree and work your way toward the top as you go. This will allow space for new growth and let sunlight in to the core of the holly tree.