How to Kill Weeds in a Back Garden Landscape on a Half-Acre Property

Lay down six to eight layers of newspaper to remove grassy weeds in large areas where ornamental flowers will be planted. Use newspapers that contain black and white ink. Spread a 2-inch layer of compost over the newspapers to keep them in place. Create holes in the newspapers and compost in which to plant ornamental plants.

Place a piece of landscape fabric or plastic over a large area of annual weed growth. Cover the landscape fabric or plastic with a 3- to 4-inch layer of mulch. Covering annual weeds with landscape fabric or plastic generates enough heat during the summer to kill weeds and seeds. Wait six weeks to plant ornamental plants.

Spray large areas of perennial broadleaf weed growth with a herbicide that contains glyphosate. Because there are no selective herbicides available for broadleaf weeds in garden beds, gardeners must use a broad spectrum herbicide for these areas. Follow the label instructions for dosage.

Kill perennial grassy weeds such as bermuda grass in flowerbeds using a selective herbicide that contains fluazifop. Fluazifop is chemically formulated to kill perennial grassy weeds without harming broadleaf ornamental plants. Follow the label instructions for dosage.

Cut a 2-liter bottle in half. Place the half with the opening over the top of a weed growing next to an ornamental plant. Spray herbicide that contains glyphosate through the opening to kill the weed, keeping the chemicals off of surrounding ornamentals.

Distribute pre-emergent herbicide granules over the garden area in the spring. Use a pre-emergent herbicide that contains trifluralin to prevent annual weed seeds from germinating. Apply 1 inch water over the garden area after applying the pre-emergent herbicide. Again, follow the label instructions for dosage.