Weed barriers are layers of woven or non-woven geotextile material used in landscaping to suppress the growth of unwanted plants. Their primary function is to block the sunlight necessary for weed seeds to germinate and sprout, while still allowing water and air to pass through to the soil below. This maintains a healthy environment for established plants. The physical barrier reduces the need for manual weeding or chemical herbicides. Landscape fabric also helps conserve soil moisture by reducing the rate of evaporation. When installed correctly, this method provides a long-term solution for keeping planting beds tidy and reducing competition between weeds and desirable plants.
Prepping the Planting Area
Preparing the ground is the first step for successful weed barrier installation, ensuring the material lies flat and functions effectively. Begin by removing all existing vegetation from the area, including perennial weeds and grasses, as remaining root fragments can regrow and penetrate the barrier material. Once weeds grow through the fabric, they become difficult to manage.
The soil surface must be cleared of debris, such as sticks, stones, or sharp rocks, that could puncture or tear the barrier. Use a rake to smooth and level the soil, eliminating major dips or mounds to ensure continuous contact with the ground. If the soil requires amendments or fertilizer, incorporate these products into the top layer of soil before the barrier is positioned.
Techniques for Fitting the Barrier Around Established Plants
Fitting the weed barrier around existing plants requires careful cutting to avoid damage or compromising the barrier’s integrity. The fabric must be cut to accommodate the stems or trunks of plants already in the ground. Two primary methods exist for achieving this, depending on the plant arrangement. For any method, ensure the fabric sheets are cut to size, accounting for an overlap of 6 to 12 inches where seams occur, which prevents weeds from emerging through the gaps.
The Slit Cut
The slit cut method is used for plants situated in a straight line or row, such as shrubs or perennial flowers. To execute this, measure the distance from the edge of the fabric to the center of the plant’s base. Starting from the edge, use a sharp utility knife or scissors to make a single, clean slit that extends inward to the point where the plant stem will be centered.
Gently slide the fabric around the plant, fitting the cut edge snugly against the stem. The overlapping sections of the slit should lie flat against the soil, covering the entire base area. Secure the exposed cut edges with landscape staples to prevent the fabric from shifting and exposing the soil underneath.
The Collar/Circle Cut
The collar or circle cut is suited for isolated plants, trees, or shrubs. Place the fabric over the plant’s base and mark the center point above the stem or trunk. Fold the fabric in half, then into quarters, ensuring the marked center point is at the corner of the fold.
Using sharp scissors, make a small, curved cut at the folded corner, creating a hole that expands into a circle when unfolded. The circle should be large enough to fit around the plant’s stem without touching it, leaving a 2 to 3-inch gap or “collar” of bare soil around the base. This area allows the stem to expand as the plant grows and prevents moisture accumulation against the trunk, which can cause rot or disease.
Anchoring the Barrier and Finishing the Bed
After the weed barrier has been cut and positioned around the established plants, the next step is to secure it firmly to the ground to prevent wind or movement from displacing it. Landscape staples, which are U-shaped metal pins typically 6 inches or longer, are the most common anchoring tool. These pins should be pressed through the fabric and into the soil every 12 to 18 inches along all edges and seams, and every 2 to 3 feet across the body of the fabric.
Securing the overlapping seams is important, as these are the most vulnerable points for weed breakthrough or lifting. For added stability, especially in windy areas or on slopes, the fabric edges can be buried in a shallow trench, about 2 to 3 inches deep, which is then covered with soil. The final step is to cover the entire barrier with a top dressing to protect the fabric from ultraviolet (UV) light degradation.
A layer of organic mulch, such as shredded bark or wood chips, or inorganic material like gravel or decorative stone, should be spread evenly over the fabric. This covering layer should be maintained at a depth of 2 to 3 inches, which is sufficient to block sunlight from reaching the fabric and maintain a neat appearance. The mulch also helps stabilize the barrier and assists with soil moisture retention for the plants.