The fruitless mulberry is a common shade and street tree in the Morus genus--several similar varieties exist. All varieties are tall--up to 60 feet--and have an attractive canopy of large, lobed leaves that fall in autumn. When the tree is bare and dormant, you need to prune it. Trimming a fruitless mulberry can be a big job if you skip even one year, because branches can grow 15 to 20 feet in one season. The method used for trimming a fruitless mulberry is called “pollarding”--this technique involves trimming off all branches from the main trunk.
Trim your tree in winter, when your fruitless mulberry has dropped all of its leaves. Assess the size of your tree and the size of the job--if your tree is very tall and its branches are long, consult with an arborist before you begin.
Cut every branch on the outer side of its branch collar using loppers, a hand tree saw or chain saw. Take care not to cut into the collar or the main trunk. The tree will look almost like a tall stump when you are finished trimming it because all of its branches will be gone.
Prune the top branches from younger trees to help train them into a spreading, attractive shape. Do not top older trees after you have trained them.
Spread a layer of pruning tar over all areas that you have cut to help protect it from insects and diseases that might enter through these vulnerable places.
Dispose of your cut branches by either taking them to your municipal green waste center or grinding them with a chipper/shredder. You can use ground-up fruitless mulberry branches as mulch around your tree and in other garden areas. Or, add them to your compost pile.