I have the same problem with several trees but the worst is with a crab apple tree. It is about 25 years old and has had sucker roots for a long time. They appear to look just like the crab apple tree. I have pruned them at ground level every year and now they completely encircle the tree about a foot larger in diameter. It looks terrible and has become too difficult to prune every year. Should I brush full strength Round-up on them?
Certified GKH Gardening Expert
Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-sucker-removal-and-tree-sucker-control.htm