Doff WeedOut Xtra Tough Weedkiller is ideal for the control of annual and perennial weeds (grasses, docks, nettles, willow herb, dandelion). It is a systemic weedkiller that works by transporting the weedkiller down to the roots. It is inactivated immediately on contact with the soil and is broken down naturally in the soil so treated areas can be replanted. Concentrated formulation. Contains 7.2g/l glyphosate as a ready-to-use formulation and 90g/l glyphosate in concentrate version.