Coco Coir Tree Rings, Set of 2

If you're not diligent about replenishing bark mulch, it can start to 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.