Weedol Lawn Weedkiller 500ml Kills weeds not the grass One treatment Controls most common broad-leaved lawn weeds 500ml will cover up to 333m2 Kills dandelions, daisies and clover Weedol� Lawn Weedkiller (Liquid Concentrate) is a selective weedkiller that controls most common broad-leaved lawn weeds without harming the grass. With season long control it only requires one treatment per year. Ideal for spot treatment or treating small patches of weeds within the lawn. The best time to treat lawn weeds is between April-September when the weeds are actively growing on a dry calm day.