Long wild grasses around edges

Can anyone help with my problem about grasses. I have a lot of wild grasses growing all around my garden in particular right along all lines of fencing. It is long grass with tough stems and the tops are kind of like a ryegrass. They grow wherever fencing meets a border.

My question is how do I get rid of it all, other than constantly pulling it out by the handful?? Is there some insecticide that will nuke it all if carefully applied so not to go onto other shrubs etc??