The common hackberry tree typically grows between 40 and 50 feet tall and wide. The tree requires regular pruning during the first 15 years of growth to avoid weak branches and multiple trunks. Because the common hackberry is prone to damage from storms, particularly ice storms, you must promote strong limbs through the regular pruning of weaker branches.
Prune small, low-hanging, misshapen or broken branches that measure less than one inch in diameter. You should perform this type of pruning year-round. Make one clean cut outside of the swollen area where the branch meets the tree trunk, known as the branch collar.
Remove large branches during the dormant period of late fall to early spring.
Make an undercut on the branch 8 to 12 inches from the tree trunk. This cut ensures the bark does not rip down the tree trunk when you remove the branch.
Create an overcut above the undercut and sever the branch, leaving an 8- to 12-inch stub.
Repeat the undercut and overcut process to remove the remaining branch stub. The final cut should occur at the branch collar.
Prune the lowest-hanging branches first by making an undercut an inch or so past the branch collar, the area that connects a branch to the trunk of the tree. This will prevent the bark from ripping down the tree trunk during branch removal.
Cut through the branch several inches farther up the branch and remove the branch completely.
Remove the stub by cutting through the branch as close to, but not into, the branch collar area as you can.
Check farther up the tree for double leaders or multiple trunks. These will become visible when the bottom branches have been removed.
Remove excess branches, leaving only one main tree trunk.
Prune dead or diseased tree branches year-round.
Choose trees to be pollarded. There are many varieties that take well to this process. Likely candidates include Striped Maple, Acer pensylvanicum; Catalpa, Catalpa spp.; Black locust, Robinia pseudoacacia; Willow, Salix spp. and Horsechestnut, Aesculus hippocastanum.
When growing a tree intended for pollarding, cut back the central leader (top upright of the main trunk) to the level of the lateral branches. Remove branches that cross other branches and remove lower shoots from the trunk of the tree. Allow the trunk of the tree to grow about 6-feet tall.
Begin in late fall or early spring. This is true for most of the species that can be pollarded. Acer varieties should be pollarded in summer, but not in extra-dry conditions.
Prune the tree. Cut back all or most of the branches to 1 to 2 inches from the main stem. This will cause a many closely spaced shoots to appear from the top of the tree. Immediately cut off any shoot growing out farther down on the trunk.
Pollard every 1 or 2 years. The new stems should be cut back every year, or every other year, to encourage new growth. Waiting any longer could damage the tree. Cut the new growth back close to the main trunk without cutting into it.
Prune in late fall, after the bulk of the nuts have already fallen from the tree. Identify the main leader, or the primary trunk of the tree. If the tree is under 5 years of age cut off the top third of this primary leader. Remove any other branches that are competing with the primary leader as these will cause weakness in the tree later on. Remove these secondary leaders all the way back to the main trunk.
Cut out all dead wood, weak branches or any wood that appears diseased.
Cut out all branches that cross each other or which are growing horizontally across the main canopy of the tree. Remove any branches which are growing at a downward angle.
Remove branches that are growing out of the trunk too closely together. If branches are growing out of the trunk within 6 inches of each other remove the smaller of the branches, leaving only the strongest.
Pinch or cut off any suckers that are growing out of the trunk or the roots. Suckers can be identified by the fact that they have no true bark, only a smooth skin.
Perform major pruning in late winter. Prune very sparingly in the summer months. Remove any root suckers as soon as they appear, usually during summer.
Cut all dead and diseased branches first. Remove any old fruit that is still in the tree.
Step back and look at your tree. Decide which branches must be trimmed for your tree to cast a nice appearance and to be balanced. Remove branches that do not add to the tree's shape or balance. Branches may be cut near the ends to create shape or may be cut next to the trunk. Leave three to four horizontal branches below the primary up-thrusting branches.
Cut back the main up-thrusting leader branches, leaving approximately 25 inches of each branch.
Remove all branches that have a narrow branching angle that is blocking sunlight and air flow to the interior of the tree.
Cut back all new growth from the previous summer to approximately 30 inches.
Cut damaged and dead branches once the shrub finishes flowering in spring. Remove these branches where they join the nearest healthy wood, making the cut flush with a healthy branch. If you're trimming a damaged branch tip, make the cut within 1/4 inch of a healthy leaf or leaf bud.
Thin out crossed branches that are rubbing together. Prune the crossed branch back to the nearest main stem. Thinning out these branches allows more air circulation through the shrub, which may help prevent diseases.
Prune overgrown branches to maintain the height and shape of the daphne bush. Cut no more than a fourth of the branches length, making the cut within 1/4 inch of a leaf or leaf bud. Daphne bushes have sparse foliage on the interior and do not bounce back from severe pruning, so keep the pruning cuts within the dense foliage closer to the branch tips.
Remove any deadwood, including twigs and branches, at any time of year. Deadwood places additional stresses on the tree and uses resources better suited to growth and flowering. Remove deadwood about the size of a pencil or smaller with a pair of pruning shears. Remove larger deadwood with a pruning saw.
Prune branches starting from the bottom of the tree to the top. Remove branches at the collar, or swelling where the branch to be pruned grows from the larger trunk or branch. Leave a bit of the collar on the branch or trunk.
Prune the tree from the inside of the tree to the outside twigs once the lower branches have been removed to your satisfaction. Use the same technique with pruning shears for branches smaller than about the width of a pencil and a pruning saw for larger branches.
Prune your tree at the recommended time. Different trees should be pruned at different times. For most trees, winter pruning is safe. For other trees, pruning after the growing season is best. Check with a reputable nursery for the best time of year to prune your particular variety.