How to get rid of tree root suckers?

For years I've battled cutting back tree root suckers/shoots from a type of flowering apple tree I have. They shoot up from its roots all over my garden and is spreading farther this year. I don't want to kill the tree but i would love to find something that will stop the growth of the suckers once i've cut them back, they are just veracious growers. Can anyone suggest something to try? I'd greatly appreciate it.