Autumn Purple, or Junginger, a wild variety of American white ash selected for its purple leaf color, was discovered by University of Wisconsin horticulturist Karl Junginger of McKay Nursery in Waterloo, Iowa. After its introduction in 1956, it quickly became the most popular and most expensive landscaping selection, surpassing the high priced ginkgo, London plane and white/burr oak. A related species, Biltmore ash, is sometimes treated as a variety of white ash. Other taxonomists argue that Biltmore ash is its own species ("Fraxinus biltmoreana").