Ruth Rogers Clausen, a horticulturist trained in England, has been living and working in United States for many years. Over her long career she has taught and lectured widely. Former horticulture editor for Country Living Gardener, she has written several books, including 50 Beautiful Deer-Resistant Plants.
Edmund C. Snodgrass started the first green roof nursery in the United States and has collaborated on green roof research with colleges and universities. A fifth-generation farmer and nurseryman, he is owner and president of Emory Knoll Farms Inc. and Green Roof Plants in Street, Maryland, specializing in plants and horticultural consulting for green roofs.