Prevent tree and shrub roots from damaging hardscapes, such as sidewalks, buildings, retaining walls, and BioBarrier, Old Hickory, TN, with Biobarrier Root Control System. Nodules slowly release trifluralin, preventing root tip cell division — the method by which roots grow. Creates a zone of protection on all sides of nodules. Place Biobarrier in narrow trench where protection is needed. Standard drainage fabric allows , air, and nutrients to pass through. Ideal for around pipes, under pots, along hardscapes, and in dams and levees.