Broken concrete, in sizes approximately 4 inches thick by 12 inches wide by 24 inches long, can be stacked for garden walls. Leave pockets for plants spaced along the wall. Working with these can be very hard on the hands so wear heavy gloves. For patios, odd shapes of concrete result in a flagstone appearance and lend themselves well to interplanting. An acid stain will give concrete a more stonelike appearance.
Used bricks can be less expensive and more attractive than new ones in a rustic garden setting.
Beware of using brick from the inner layers of thick brick walls or from buildings that have burned. As your recycling experience grows, so will your imagination and quick eye. There are even stories of one gardener who used bed springs to trellis cucumbers. More gardening information is available in the Virginia Gardener Newsletter .