Robert NoldRobert Nold is a regular writer for the rocky Mountain Chapter of the North American Rock Garden Society and the Colorado Gardener. His articles have appeared in The American Gardener and Horticulture, and he was a contributor tothe 2004 revision of The American Horticultural Society's A-Z Encyclopedia of Garden Plants. He is the author of two award-winning Timber Press books: Penstemons and Columbines. Read More Read Less