There are two main classifications used to describe the types of herbicides available for killing weeds in your lawn. It is extremely important that you choose the correct one for the situation. Incorrect use can lead to disastrous results, particularly if it involves blanket spraying a non-selective herbicide.
The answers as to how these types of herbicides function lie in the names.
Selective herbicides are ‘selective’ – they only work on a particular type of weed or grass and if used as advised will only harm the intended target and not everything they come in contact with.
Bindii, clover, oxalis and many others – your common broadleaf weeds, can all be targeted with a selective herbicide. There are however selective herbicides that are not safe for use on all grass types. This is where it is very important you read the label and only apply the herbicide to a turf variety that it’s safe to use on. Buffalo grass for example, requires a specific type of active ingredient, usually Bromoxynil. Selective herbicides with the active ingredient Dicamba will harm the weeds as well as your buffalo lawn.
On the other hand, there are the non-selective herbicides. There are fewer options with these herbicides, but the key ingredient is almost always glyphosate. Some brands include Round Up and Zero and as the names suggest, non-selective herbicides will definitely not be selective and will harm any living plant species they come in contact with.
Some weeds are difficult to control as there are either no selective herbicides available or they are extremely price prohibitive. In this situation a non-selective herbicide may be your only option. But remember, these herbicides will kill everything they contact. Application is recommended only when hand removal has failed or isn’t an option. If very carefully applied, using a small paintbrush where you can ensure that only the weeds you are targeting come in contact with the non-selective herbicide, then it may be effective.
Generally speaking, though, non-selective herbicides are best used for blanket spraying before installation of a new lawn, for stopping the spread of runners or weeds via edging or for targeting weeds in concrete areas of garden beds where you can easily target the weed or grass without affecting the surrounding plant life.
Save yourself the heartache like the image above! Always carefully read the label of all products before applying to your lawn.