We recently purchased a house that had long been neglected, inside and out, for probably well over a decade by the previous owner. It took me some months to fix up the interior, and then a couple of months ago I started work on the yards. The back area was a nightmare, literally a jungle of hundreds of potato vines hanging down in sheets from the 6 - 8 trees located there, palmetto palms everywhere, termite infested dead trees lying on the ground or ready to topple over - seriously, two thirds of the yard was impassible because of all the overgrowth. It took me well over a month to clear it all out, and I filled a 20 yard dumpster with all the debris - and that with me constantly jumping up and down on the stuff to pack it all down to make more room! All this from and area about 30' deep and 100' across!

I spent a number of exhausting days digging up stumps and the bases of the palmetto palms (are they a pain to dig out!) and then moved on to tearing up the overlayed webs of root systems (from the potato vines?) spreading out in all directions, some runners as long as 20' - 30' and others as thick as 2", and though I think I've got most of the major ones there's still bits and pieces here and there, and I'm concerned that they might sprout back up once I lay the new lawn down in the area. I don't know how effective it is on them, but I went through the whole area once I'd finished and sprayed it with the redcap version of Roundup to kill off the remaining grown, and mixed it stronger than usual in the hope it might have some effect on these root systems. I thought of using the purple version of Roundup, as I've read it will kill EVERYTHING, but I'd also been told that once you do you won't be able to grown anything in the area for a year or so.

I don't want to go to the trouble of laying down a lawn, now that I've gone to all this effort to clear up the area, only to have the vines sprout up again through the grass, so what would people advise? Would a strong lawn cover be enough to deter these roots doing anything, or should I hire a soil tiller to really dig through the soil and rip up and cut all these remaining roots? Bear in mind that I'm also a little limited in how far I can go as far as tilling the soil, because I still have the trees in the back with their own root systems, so I have to be careful not to cut into their roots, as well as the fact that some of the root systems I'm looking to remove will be unreachable because they're intertwined with the tree roots, as I've already discovered.

Thanks in advance