We hired someone to cut down a pear or peach tree 2 years ago. He cut it down and got most of the big roots around the base but a lot of the roots still remained. I literally have been removing big and small roots every few weeks and have caused a lot of soil erosion, but new growth keeps coming back and I constantly discover more roots, some that are too deep for me to manually remove. New growth continues to sprout up throughout my garden in many places that our 5-20 feet away from where the original tree was. How do I permanently kill the tree roots and prevent new growth? I would like to preserve the soil around where all the roots are to plant new flowers and shrubs. Do you have any advice?