Performance of Landscape Plants from Yugoslavia in the North Central United States

Abstract

From 1975 through 1979, 38 new, landscape plant introductions from Yugoslavia were distributed for testing in the NC-7 Regional Landscape Plant Trials. Twenty-seven of these introductions were evaluated for 10 years at seven or more sites, representing a broad range of environmental conditions in the north central United States. For these 27 introductions, first-year survival averaged 71%. Only four introductions had less than 50% first-year survival. Tenth-year survival varied widely among introductions and trial sites. Eight populations were adapted to most trial sites, ten populations were adapted to some sites, and nine populations were not adapted to any site. The most promising and broadly adapted introductions were Viburnum opulus, Pinus sylvestris, and Pinus nigra. Temperature and moisture data from Yugoslavia and from trial sites were used to examine relationships between plant adaptation and climate. Statistically significant, multiple-regression models were calculated that describe the functional relationships of low temperatures and moisture conditions at trial sites with adaptation. The models predict that these plants are best adapted to sites with winters milder than those typical in the north central United States and with precipitation in excess of potential evapo-transpiration.

Environmental Analogs in the Search for Stress-Tolerant Landscape Plants

“…The 10-year evaluation results of Yugoslavian landscape plants indicated that only about a third of the populations survived and generally performed well throughout the north-central United States, another third failed at the colder or drier sites, and the remaining third failed at all sites (50). Statistically significant multiple-regression models, based on low winter temperatures and 1.…”

“…The most common measure, mean annual minimum temperature, serves as the basis of important hardiness zone maps for North America (6,34) and for Europe (14). Other studies have evaluated January mean temperatures in comparison with mean annual minimum temperature to predict the survival of selected woody plants in the north-central United States (50) or incorporated the monthly mean of daily minimum temperatures of the coldest month (MMDM) into multiple regression equations and maps for general woody plant adaptation in Canada (28,29). The MMDM also was the climatic statistic that was most congruent with boundaries of forest plant communities in Florida (13).…”

“…Long-term moisture deficits and surpluses can be analyzed by comparing PE with mean annual precipitation. One method of expressing the balance between PE and precipitation, Mather and Yoshioka's (24) moisture index, has helped predict the distribution of plant communities (24) and is a statistically significant variable, along with January mean temperatures, in predicting the survival of woody plants from Yugoslavia at test sites in the north-central United States (50).…”

“…With this very long "preface" complete, I will now describe an ongoing effort to locate and acquire potentially useful trees and shrubs native to Eastern Europe, for testing in the north-central United States. This project began in a rather unsystematic fashion in the mid-1970s, with the introduction to the United States of a diverse set of woody plant populations from the former nation of Yugoslavia (50). Many of these populations were evaluated at sites throughout the north-central United States as part of the NC-7 Regional Ornamental Trials, a long-term project to evaluate new landscape plants and to increase the future diversity of well-adapted plants found in commerce (48).…”

Models for Predicting the Risk of Naturalization of NonNative Woody Plants in Iowa

“…herbivory, niche competition, disease) rather than climatic ones (31). It has been demonstrated, however, that climatic factors are important determinants of non-native woody plant survival in the North Central United States (40,41).…”