My neighbour’s large Manitoba maple fell down in my garden a few years ago. A very good arborist cleared it all away and now, with my neighbour’s permission, I trim the green shoots from the remaining stump every spring and fall and put the shoots out for the city to take away.
I enjoy pruning the stump and it takes only about 10 or 15 minutes. Will the green shoots eventually stop growing, though, and will the stump and roots die because there are no leaves for photosynthesis? How long might that be? There seem to be fewer new green shoots appearing on the stump each time I prune.
Thank you for contacting Toronto Master Gardeners about the Manitoba maple (Acer negundo) you have been pruning. This species of tree is native to much of North America. However, it is often considered aggressive in residential yards. A. negundo may continue to send up shoots from its stump – and even from its roots, which tend to be shallow – years after it has been cut down. With diligent and continuous pruning, which is often required several times a year, it is likely that the tree will eventually cease to grow new shoots, as it will deplete its energy stores over time. The absence of leaves will prevent the tree from photosynthesizing and replenishing those lost stores. However, it is difficult to provide an exact timeline for how long this will take. When pruning, try to cut as close to the stump as possible and be on the lookout for any suckers that may have emerged from the surrounding root system. If you have a good relationship with your neighbour, you may want to discuss the possibility of having the stump removed by an arborist.