Consider other options for weed control, such as hand pulling or mulch, if borax is ineffective against the weeds you wish to kill, such as clover, dandelions or plantains, or if the weeds are growing around plants that may be damaged by herbicides, advises the Iowa State University Extension.

What weeds does borax kill?

Borax is particularly effective at killing creeping Charlie, also known as ground ivy (​Glechoma hederacea​), on bluegrass (​Poa pretensis​). If you have areas on your property where you don’t want any vegetation to grow, you can apply borax more freely.

What will kill dandelions but not grass?

A broadleaf herbicide is good for killing dandelions in lawns, as the herbicide will kill the dandelions and not the grass. The other kind of effective dandelion herbicide is a non-selective herbicide. Non-selective means that the herbicide will kill any plant that it comes in contact with.