Brushtox Brush Killer with TriclopyrBrush Aside Invasive Plants And Weeds Arm yourself with our newest weapon in the fight against more than 60 woody plants including mesquite, oaks, locust, wild rose and sweetgum and 30 tough broadleaf weeds like Canada thistle and dog fennel. See label for complete list of weeds. Brushtox is a concentrated herbicide that works both economically and effectively on rangeland, permanent grass pastures, fencerows, ditch banks and rights of way on acreage