Book excerpt: This book introduces a revolutionary new concept to gardeners. Planting on roofs and walls began in Europe, but it is now becoming popular all over the world. Green roofs and walls reduce pollution and run-off, and also help insulate and reduce the maintenance needs of buildings. Planting Green Roofs and Living Walls discusses the practical techniques required to make planting on roofs and walls a reality. It describes how roofs may be modified to bear the weight of vegetation, considers the different options for drainage layers and growing media, and lists the plants suitable for different climates and environments. This informative book will encourage gardeners everywhere to consider the enormous benefits to be gained from planting on their roofs and walls.