If you're not diligent about replenishing bark mulch, it will look messy and start letting weeds through after just one season. These thick mulch mats are made of tightly woven coconut fibers and durable natural latex, so they stop weeds for several seasons. They reduce string-trimming chores too, because you can mow right over them. Lightweight and easy to work with; slips easily around a tree trunk These rings last three years or more! Permeable to water, air, and plant nutrients Center hole is easily enlarged if needed Earth Staples (sold separately) keep the rings in place permanently Choice of four sizes: 24", 36", 48", and 60" 24", 36", 48" or 60" diameter Made of woven coconut fibers and natural latex Gardener's Supply Exclusive