Dirr's Encyclopedia of Trees and Shrubs3500 photographs. Over 380 genera. More than 3700 species and cultivars. Dirr's Encyclopedia of Trees and Shrubs is the most comprehensive visual reference to more than 3700 species and cultivars. From majestic evergreens to delicate vines and flowering shrubs, Dirr features thousands of plants and all the essential details for identification, planting, and care. Color photographs show each tree's habit in winter, distinctive bark patterns, fall