This comprehensive perennial guide includes 20 years of performance data from Colorado State University's W.D. Holley Plant Environmental Research Center. Plant performance was rated and top performers are described according to: landscape use, height, foliage, color and fall effect, winter injury, ornamental fruit, disease and insect problems. These top-performing perennials are ideal for xeriscapes, rock and wildflower gardens, and the traditional perennial border. Also includes plants that attract butterflies and hummingbirds,and 5 bloom charts for white, yellow/orange, red/pink, and blue/purple flowers. An absolute MUST for the Colorado, Rocky Mountain or High Plains gardener.