With the right tools on hand, you can kill offending grass in your yard without harming the broadleaf plants you worked so hard to establish. The most common ways to kill grass lawns or grassy weeds are with herbicides and digging. The method that you apply largely depends on personal preference and the amount of labor you are willing to put in. Whichever technique you use, take a few simple precautions so your broadleaf plants stay safe.
Choose a selective post-emergent herbicide listed for use on the type of grassy weed you want to eradicate. These selective herbicides target grassy plants and will not harm most broadleaf plants.
Spray grass with the herbicide early in the morning or late in the afternoon. High temperatures can cause any herbicide to burn your broadleaf plants. Wait for a day with very little wind to minimize the risk of the wind carrying the grass herbicide to your broadleaf plants.
Cover you broadleaf garden plants with plastic sheeting if you intend to kill your grass with a broad spectrum herbicide such as glyphosate. This will ensure that the broadleaf plants are protected from any accidental sprays.
Dig up the grass. This is certainly the most labor-intensive way to kill grass, but it is the safest for any neighboring broadleaf plants. Use a trowel to dig up small patches of unwanted grass, avoiding any broadleaf plant roots growing nearby. Use a flat-edged shovel or sod remover to dig up larger areas of grass.