When you are preparing a landscaping area that will contain decorative mulch, you should remove any existing grass from the area before adding the mulch. If you do not properly remove the grass, it will eventually grow through the mulch and give the bed an unsightly appearance. Take the time to kill the grass completely before mulching for a landscaping job that will stay attractive for many years.
Mow the grass first so that it is as short as possible.
Use the rototiller or garden spade to work and loosen the soil and break up the grass. Work the soil thoroughly down to a depth of 4 to 5 inches. Rake the soil surface smooth.
Add sheets of newspaper or black plastic over the entire surface area of the grass you want to remove. If you are using newspaper, apply the newspaper in layers of approximately 10 newspaper sheets. Make sure to overlap the newspapers or black plastic so that there are no gaps. Saturating the newspaper with water after laying it down helps to keep it in place.
Place heavy rocks on the corners of the newspapers or plastic to hold the coverings in place.
Leave the black plastic in place for as long as one month to kill the grass. Remove the black plastic and apply the mulch as desired. If you used newspaper, it is not necessary to pull the newspapers up again. You can apply mulch directly over the newspapers immediately after laying them down, if desired.