Mulches cover the soil and are used to minimize evaporation, reduce weed growth, cool the root zone and slow erosion. Mulches can also give beds a finished look, increasing a garden’s visual appeal. Apply bark mulch directly to the soil surface or rock mulch over a landscape fabric.
Organic mulches, such as bark chips, pole peelings or wood shavings should be applied in a layer 4 inches deep. Organic mulches decompose and improve soil texture, but they must be replenished periodically.
Other mulches such as rocks or gravel should be applied in a 2 inch layer. They rarely need replacement and are good in windy spots. Rock mulch can increase heat to the soil which not all plants can tolerate.
Landscape fabric is an option to reduce weeding. Don’t use black plastic in areas that have plants; it prevents air and water from reaching plant roots. Many xeric designs do not use landscape fabric as the spreading of plants is desired to provide a full, filled-in look. Also, bark mulch will stay in place better when not placed on fabric.