I like the idea of a 2ft concrete barrier. I did this around my cabin. A good slope drains water away from building and prevents dirt from splashing up on siding. Drive on the concrete while mowing. Plus it seems to keep all sorts of critters from burrowing around the perimeter. I put lava rock around my house....looked nice for a couple years, but with all my trees it started filling with sticks, twigs, leaves and them darn helicopter looking seeds from the maples. Tried cleaning with gas powered vacuum but collected more lava than leaves. And I just hate the sound of my blower trying to mulch rocks! Roundup sounds like the easiest and quickest solution in my mind.