Pathclear Gun! Weedkiller Plus Preventer has been specially formulated for gravel paths, drives and waste ground. It contains a systemic weedkiller to kill off existing weeds right down to the roots and a residual weedkiller to prevent new weed seeds from germinating. It works by killing the leaves and roots of existing weeds and creating a barrier in the soil that prevents new weeds from growing for up to 3 months. It is effective against annual and perennial weeds.