Keeping weeds and vines away from your chain-link fence can be tricky, but not impossible. Two of the best options for keeping grass and other plants at bay are using a weed eater or treating the vegetation with a post-emergent herbicide.  When using a weed eater, wear protective gear such as safety glasses, ear protection, and clothing that protects your body from any possible flying debris. Herbicide treatments can be an effective way to keep your fence line free of unwanted brush and weeds. If you have weeds growing near or on your fence, a post-emergent herbicide should do the trick by killing all parts of the weed, including its roots. To prevent weeds from sprouting, apply a pre-emergent herbicide.