Book excerpt: Trees and shrubs are a valuable asset to a garden bringing structure, shade, year-round interest and the all-important vertical dimension. But choosing the right ones for small gardens is a fine art, and it's all too easy to end up with heavyweight shrubs overtaking the border, dysfunctional climbers and trees outgrowing their designated spaces. In this practical reference, woody plant expert Diana Miller takes the anguish out of the process by recommending plants and cultivation techniques that excel in small garden spaces. Small gardens require careful planting, and the book starts by considering plants that fulfil a particular design function, such as trees that provide the right levels of shade for an underplanting of choice bulbs, columnar or weeping trees for very restricted spaces, and specimen shrubs that provide an effective foil for herbaceous perennials in a mixed border. At the heart of this book is a comprehensive plant directory that provides detailed descriptions, including full cultivation advice for over 400 top-performing trees and shrubs. Further advice on pruning, information on planting to encourage wildlife and handy lists that allow readers to search by colour, height and other characteristics are invaluable.