Plastic Landscape Timber Edging | Home Guides | SF Gateplastic landscaping timber edging is made with recycled plastic from everyday items. ... plastic timbers will also expand. Unlike real wood, which contracts as well, plastic landscape timbers do not reclaim their original shape. Manufacturers typically specify the amount of expansion expected in the product literature. While it is weatherproof, plastic landscape timbers will also warp if they are ... When buying plastic landscape timber edging, look for a product that contains a UV stabilizer.