Many weedkillers are selective; that is, they are formulated to target specific weed species only. This is why you can use selective weedkiller on lawn weeds without harming the grass.
They only target ‘dicot’ plants – those that typically have broad leaves. They will not work on ‘monocot’ plants like grasses and corn.
Monocot and dicot plants have different metabolic pathways, and a selective weedkiller only takes advantage of the metabolic pathway of dicot plants.
Their well-known cousin is the broad-spectrum herbicide – formulated to kill most plants they come into contact with. These weedkillers are mostly used in hard landscapes, not lawns or grassland, and kill weeds by disrupting the weed’s ability to photosynthesise.
Encouraging growth
Selective weedkillers on the other hand work by encouraging the weed to put on unsustainable growth.
Odd though that might sound, they contain specific growth hormones known as superauxins that cause the weeds to grow at too quick a rate, meaning they effectively grow themselves to death.
The selective herbicide is absorbed through the foliage then essentially ‘interferes’ with cell formulation resulting in abnormal root and shoot growth. This action disrupts the growth process to such an extent that the plant dies.
Selective lawn weedkiller
While trees and shrubs are less sensitive to selective herbicides, annual lawn weeds like dandelion, buttercup, clover, and daisy respond well – especially when they are in the earlier stages of growth.
A selective herbicide like Dicophar is highly effective at tackling these types of weeds in lawns and amenity turf and can be applied right through the summer months
Selective pasture weedkiller
Selective herbicides work in the same way on paddocks and pasture grassland and can use variations in ingredients to tackle weeds that are commonly found in these environments.
Grazon Spot targets paddock weeds like dock, creeping thistle, and common nettle. It will also effectively control a wide range of other annual and perennial weeds, and like Dicophar can be used right through the summer.
Grazon Spot is fast acting, rain-fast in two hours and completely harmless to grass, with grazing resumption in just seven days.
For more information and tips on paddock care, see our library of guides here.
For more information and tips on lawns and amenity turf, you can access our ‘how to’ guides here.
