AS THEIR NAME
suggests, contact weedkillers kill plants on contact – allowing you to focus your efforts on those parts of the weed you can see, above ground. This makes them ideal for annual weeds (that can’t regrow from their roots) and to ‘burn off’ the foliage of perennial weeds. How do they work? They use naturally occurring chemicals such as fatty acids, acetic acid and pelargonic acid to damage the protective covering of the leaves so they dry out and die within a matter of hours. Why would I buy them? These weedkillers are more effective at low temperatures than systemic weedkillers (containing glyphosate see over). Many products refer to ‘Fast Acting’, ‘Superfast’ and ‘Ultrafast’ – instant results make them a popular choice. Some contact weedkillers also contain the plant growth regulator hydrazide, which works down to the roots to impede regrowth.