I've cut and cut hundreds of them but they keep coming back. I heard, the more you kill the root suckers, it tells the tree to make more. This tree is my only tree in the front yard. I did see something called "Sucker Stopper". . . . but I haven't tried it. It's $28/spray bottle.
Do you know of something I can plant to keep these root suckers from emerging to the top? One neighbor planted "Widela". Supposedly, it is fast growing with runners and blooms a yellow flower.