I have a rectangular area approximately 7' x 20' between the walkway to my
front door and the side of the garage that has bushes against the house and
garage and the rest of it is river rock (over dirt of course).

I keep having grass intrustion. A few months ago I stipped it down to the
dirt and applied Ortho Basic Solutions Total Vegetation killer, which the
local garden shop assured me would last for years, laid down weed cloth and
the river rock. A few months later I was getting grass poking back through.

I've gone through the chore of shoveling out the river rock again and am
down to bare ground. Any suggestions regarding what can I lay down to keep
the area absolutely grass and weed free, essentially forever, or at least
several years, without killing the surrounding bushes?

All assistance will be appreciated.