I treated some weeds with glyphosate and they seem to be showing no signs of dying, whilst other weedkillers I have tried in the past, such as Kills Weeds Dead Fast!, turned the weeds brown and crispy within days of treatment. Why has glyphosate not done the same?

Glyphosate weedkillers are absorbed through the leaves of the weed and then travel within the weed to all parts including the roots. Once it has fully circulated within the weed, it then causes death. This process takes time. Weed death should be seen approximately 3 weeks after application of the glyphosate.