Winter grass killer does exactly as the name suggests – it kills winter grass selectively in your lawn. This means you can apply it to the whole lawn and it will only kill the winter grass! Winter grass is a prolific annual weed that if left unchecked can take over your whole lawn. The product works by stunting the growth of the plant, particularly the germinating seed which will start coming up in Autumn (generally speaking). Having stunted/stopped the plant´s growth, it can not spread/reproduce. Covers approximately 200m2.