Again, although there has been discussion about creosote, I have seen no effect on his roses. A new option for lining raised beds is plastic and composite lumbers. Plastic lumber is made from recycled high density polyethylene, and manufactured by several companies around the country. The material generally is available in several colors and, although ultraviolet rays degrade plastic, the product is generally guaranteed for 50 years. The company also markets a raised bed kit.
Composite lumber is a mix of wood and plastic.
It can also be worked with standard woodworking tools and standard fasteners. The product fades to a light gray over time if not painted. Paint would help tremendously. A recently available choice is the new cement wall blocks, available at most hardware outlets. The sides are slanted front to back so the wall can be curved while keeping the faces of the blocks together.