Hello, I discovered Willow roots in my sump pump hole a couple of years ago. We planted a seedling 50 feet from our house 22 years ago. The roots have gone up to the foundation, then down 10 feet into the foundation drain pipes at the bottom of the wall. Last Fall I dug up the corner - 5 feet wide and 10 feet down - and cut the root that reached down into the drain pipe. . I filled the hole with 1 inch round rocks that don't hold water, to try to make it dry so the roots can't cross through the dry rocks. However, the front of the house is 36 feet long, and I only dug 12 feet along the front. So there is still 24 feet of sand/clay along the rest of the house. I see roots up at the surface of the sand, and presume there are roots heading down into the drain there, too. I have read that sewer root infiltration is treated with either dochlobenil or copper sulfate. QUESTION: Can I saturate a border along the front of the house...about 5 feet away from the house... (sand/clay) by saturating with some concentration of copper sulfate or dichlobenil, so the roots die and don't come back? In other words, either deep root irrigation with copper sulfate solution and drip tube on the top surface, to try to soak/saturate the soil with a root unfriendly concentration of something? I want to build a front porch, but I can't until I solve the root problem that will persist beneath the front porch, continuing to clog the foundation drain and sump pump hole with roots.