ARTICLE BY: TOM FISCHER HPSO member, Tom Fischer, is editor-in-chief at Timber Press in Portland, Oregon. A prolific writer as well as an editor, his articles have been featured in magazines such as Garden Design, Gardens Illustrated, and Martha Stewart Living. His book, Perennial Companions: 100 Dazzling Plant Combinations for Every Season, was published by Timber Press in February 2009, followed by The Gardener’s Color Palette in 2010. You can read many of his articles on his website, OverPlanted.com. *** Excessive caution is as great a blight in the garden as powdery mildew or anthracnose. It keeps us from unleashing…