My new place has a weeping mulberry tree whose leaves last fall trailed all the way to the ground and even farther. It needs trimming, and my desire would be to cut it so that the bottom of the crown is perhaps shoulder height. The branches are not thicker than 2 inches at this level- more like half an inch or less, they are individual shoots not branching off branches. However, it definitely would be more than 25% of the tree trimmed, as I guess the tree is maybe 7 or 8 feet high. The last thing I want to do is make it vulnerable to disease. However, since it’s going to be 20 degrees or higher all week, I feel I better trim it imminently or the sap will run. What is a healthy amount of trimming? I may err on the side of caution and trim today and trim more if I hear back.
Weeping Mulberry is a grafted variety of mulberry (Morus alba), a 9-15m tall tree native to China, cultivated for silk worm production. The botanical name of weeping mulberry is Morus alba ‘Chaparral’. One of the purposes of grafting is to limit the tree’s height to approximately 2 to 3 m. The graft is likely visible at the trunk height of approximately 2m.
You have described your tree as “extremely overgrown” and that more than 25% needs to be pruned. This would indicate that successive pruning will need to be done over, perhaps, a three year time span to maintain the health and growth of the tree. Pruning dead, diseased and cross-over branches can be done at any time. Pruning before leaf-out helps with assessing where to prune. While you mentioned a concern about pruning before the sap runs, there is some lack of consensus as to the effect of pruning when the sap is running. Without a photo of your tree, it is difficult to give specific guidance, but you may find this video particularly helpful: Pruning a Weeping Mulberry. Ensure that all pruning equipment is disinfected before each cut. It also may be advisable to consult an arborist before pruning your large tree and also if signs of disease are present.
For further information, please click on the following links:
Pruning WeepingTrees and Shrubs
Technique Tips: Pruning Weeping Mulberry
Wishing you all the best in your weeping mulberry pruning project.