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

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 evapotranspiration