I bought a house a few months ago and there's stumps all over the yard, two feet diameter on average, all with their root systems still intact. The roots that are exposed or a foot or so under the ground are one, in the way of any kind of landscaping, and two, reshooting new trees. I'm looking at Stump Out to handle the stumps (or a grinder, I know opinions differ on that), but don't want to do that until the roots are removed in case of underground smoldering roots. I've dug some of the roots up, which is doable but will take a very, very, very long time. Is there a product or technique I can use to kill the roots before I take down the stumps?