Keeping the grass out of the borders

Afternoon all.

Separating my lawn from my borders I have a path of bricks. When I did it, my intention was that the bricks would be 'no mans land' and any plant crossing it, be it plants in the border or grass in the lawn, would do so at its own peril with great risk of being chopped or sprayed.

I didn't bargain on the grass spreading below ground.

Any ideas? I don't want to be picking grass out all the time. I want to do some work to physically isolate lawn from border, blitz the border (sounds extreme but I have plans for it anyway that require its annihilation) and then start again.

What if I lift the bricks and put some sort of membrane under or something?

 

You could use that plastic lawn edging that comes in rolls. It is available in different heights, and as you should bury it so the top is level with the grass, I think the 4" would suffice. Just bury it behind the back of the bricks.

 

The grass isn't crossing it Clueless, the roots are going underneath the bricks. Grass roots go down about 4 to 5 inches, so obviously you'll have to put something below the level of the bricks so the roots can't spread.