Three years ago I removed a pear tree. I removed the entire stump and root ball by digging all around it, cutting off the lateral roots, and levering it out. I followed the larger roots and dug them out.

The remaining roots keep sprouting up. I keep digging down and cutting them off. I've read that the roots will eventually lose energy and die, but it's been over three years.

The remaining roots go under the driveway, the sidewalk, or the neighbor's property where I can't dig them out. I've searched for solutions, but haven't found much.

I don't want to salt the ground because I'm supposed to grow other plants here.

I've read that I could brush the cut ends with glyphosate or triclopyr. I don't use pesticides or herbicides, but this may be my last resort if nothing else works.

I was thinking about using a blowtorch to burn the cut ends. Has this worked for anyone?

Any other ideas?