Boundary plants

Small plants in the border between a grass path and a polytunnel

Big Root Cranesbill (Geranium macrrorhizum) in a border by the polytunnel

Thick, clumping boundary plants prevent grass paths creeping in to borders

It’s a good idea to line grass paths with clumping boundary plants to stop ‘Grass Creep’ into the border.

Here are some suggested plants:

There will be lots of other possibilities, let me know what works for you