by CAROL BISHOP MILLER illustration by JOHN KASCHT
EVER IN SEARCH OF THE “NEXT GREAT PLANT,” the University of Georgia’s renowned woody plant expert, Michael A. Dirr, has quite possibly done more to influence the contents of our landscapes than anyone else in recent American horticulture. Through his Georgia Plant Introduction Program, this tall, powerfully built plantsman with the drive and stamina of an athlete (he plays tennis and racquetball) has brought into the nursery trade at least 64 superior selections of trees and shrubs.
“Nurseries are conservative,” explains Harvey Cotten, past president of the Alabama Nurseryman’s Association and chief operating officer of the Huntsville Botanical Garden. “It’s hard to get them to grow new plants. Mike Dirr went to the product source and said, ‘We need to get these superior new plants out there.’ He was really influential in helping young nurserymen in the South get started by persuading them to grow these new varieties his research program had developed. He’s brought academia and the industry together and moved the industry forward.”
“My personal horticultural hero,” is how southern nurseryman and hydrangea expert Eddie Aldridge describes this impassioned researcher, teacher, writer, and recipient of dozens of prestigious honors for outstanding contributions to horticultural education, research, and advancement. Dirr’s Manual of Woody Landscape Plants (See “The Horticulture 100,” May/June 2004), now in its fifth edition, is every nurseryman’s bible as well as the country’s most utilized horticultural teaching text, and The Reference Manual of Woody Plant Propagation, cowritten with Dr. Charles Heuser, is the reference of choice in the teaching and practice of woody plant propagation. Other books, such as Dirr’s Hardy Trees and Shrubs, written in the author’s engaging, humor-laced style and illustrated with hundreds of his own excellent photographs, have attracted a following among nonprofessionals as well. In recent years Dirr has gone high tech, first with The Photo-Library of Woody Landscape Plants on CD-ROM and, last year, The Interactive Manual of Woody Landscape Plants on DVD. His Web site, www.nobleplants.com, offers a window on his research, with astute plant profiles and articles and an opportunity to order from a list of choice cultivars.
Dirr credits his father for sparking his passion for plants. As children in Cincinnati, he and his sisters ran a summertime fruit and vegetable stand. He worked in nurseries and garden centers during high school and while attending Ohio State University, where he took BS and MS degrees in horticulture. “Dad thought you gardened for food,” Dirr recalls. “When I told him I was majoring in ornamental horticulture, he didn’t know what that was.” In 1972, with a PhD in plant physiology from the University of Massachusetts, Amherst, Dirr began his teaching career at the University of Illinois, Urbana. He moved to the South in 1979, first as director of the University of Georgia Botanical Garden (now the State Botanical Garden of Georgia) at Athens, and then, two years later, becoming a teacher and researcher at the university. He and his graduate students have conducted research in plant nutrition, metabolism, and cold hardiness, and have collected, bred, propagated, and evaluated a wide assortment of shrubs and trees. Recent work has focused on buddlcias, ceonothus, hydrangeas, crape myrtles, and golden spirea. Dirr’s nonstop enthusiasm rubs off on his students, with whom he enjoys an obvious rapport. “Ask 99 percent of my students,” he says, “and they’ll say, ‘I got an education; he inspired me’.”
Now 60 and eager to devote more time to his family (his wife Bonnie, an artist who furnishes illustrations for some of his books, and their three grown children), Dirr has retired from the classroom, but his woody plant program at the University of Georgia is still “cooking on all cylinders,” as he puts it, and he takes his “new plant road show” to lecture venues throughout the country. He’s just published a new book, Hydrangeas for American Gardens (Timber Press, 2004), and will soon produce another on viburnums. “It’s been a great life,” he says. “I have no regrets.”
“He’s certainly made an impact on horticulture in this country,” affirms UGA colleague and herbaceous plant authority Allan Armitage. “We’re all better off because of Mike.” H