Mulching smothers the weeds by excluding light and providing a physical barrier to impede their emergence.[1] Mulching is successful with most annual weeds, however, some perennial weeds are not affected.[2] Mulches may be organic or synthetic. Organic mulches consist of plant by products such as: pine straw, wood chips, green waste, compost, leaves, and grass clippings. Synthetic mulches, also known as ground cover fabric, can be made from materials like polyethylene, polypropylene, or polyester.[5][6] The effectiveness of mulching is mostly dependent on the material used.