Several years ago I used cedar for edging along a walkway (i.e. in the ground), needs replacing. How will this product hold up in the ground?

Hello, and thank you for your interest in Trex! Trex decking is not recommended to be installed onto a flat surface of any kind such as the ground as this prevents drainage and airflow. However please note that Trex is often used in creative applications in place of wood by many customers. For proper installation, Trex decking can be installed over a flat surface once a "sleeper system" is added. Adding in a sleeper system creates a substructure between the Trex and the flat surface below. The minimum recommended sleeper system height is 1.5". In addition the sleepers should be built using code approved structural material such as pressure treated lumber and spaced to Trex's joist spanning requirements for proper support. I hope this helps answer your question. Thanks, - Trex Customer Care Team