DeWitt Weed-Barrier 15 Year was developed as a high grade 2.2 oz. woven polypropylene fabric for the cost-conscious consumer who still wants professional quality. De Witt Weed-Barrier 15 Year is permeable, UV treated and is striped every 12 inches for plan alignment. Increased Light Blockage: The innovative weaving technology provides total weed control without the use of harmful herbicides. The lighter weight makes it easier to install, saving you time and labor cost. Plus lower freight costs improve your bottom line.