Climatic extremes and unfavorable soils limit landscape plant diversity in the midwestern U.S. Since 1983, I have coordinated the NC-7 Regional Ornamental Trials (Widrlechner, 1990) for evaluating new landscape plants in the region and for increasing the future, diversity of well-adapted plants found in commerce. I acquire, propagate, and distribute promising new plants for long-term testing at 38 sites representing the region's climates and soils. Plants for testing can come from breeding programs or public gardens, but often originate from wild collections. Selecting promising plants for testing from the native woody flora of the temperate world is not simple, especially when many species are poorly adapted to our region. Fortunately, past experiences from the NC-7 Trials may increase the likelihood of future success. For example, populations of trees and shrubs collected in the former nation of Yugoslavia were distributed for testing in the mid-1970s. Analyses of the performance of 27 of these populations in relation to climatic conditions at test sites (Widrlechner et al., 1992) may help answer the question "Is eastern Europe a useful source of new landscape plants for the midwest?"