Kousa dogwood (Cornus kousa Hans.) trees often develop unattractive leaf curling throughout canopies during hot and/or dry weather. Aesthetically superior trees were compared to control trees for their ability to tolerate summer stress, in an established kousa dogwood plantation in 2000 and 2001. An index of leaf curl revealed that superior trees showed less curling than controls during June, July and August of 2000 and 2001. Superior trees often had higher stomatal conductance than trees in both control groups during both years, with seasonal averages 16 to 40% higher in superior than in control trees. Leaf water status, characterized by leaf osmotic potential, remained similar in superior trees and control trees throughout the 2000 summer season. Leaf temperatures were similar between groups during each summer. We confirmed that trees initially selected as having superior visual appearance had measurable differences in foliar characteristics compared to control trees, and that these trees better tolerated summer stress.

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Author notes

Special appreciation is extended to Polly Hill (Vineyard Haven, MA) for kousa dogwood seeds and to the National Atmospheric and Oceanic Administration, Atmospheric Turbulence and Diffusion Division (Oak Ridge, TN) for climate data. Thanks also to Steve Schaller and Debbie Ketchersid for assistance with field data. This research was supported by special funding from the Tennessee Agricultural Experiment Station.

2Professor and corresponding author. Department of Plant Sciences and Landscape Systems. To whom reprint requests should be sent.

3Professor, Department of Entomology and Plant Pathology.

4Research Associate, Department of Plant Sciences and Landscape Systems.

5Associate Professor, Department of Ornamental Horticulture and Landscape Design.

6Graduate student, Department of Plant Sciences and Landscape Systems.

7Assistant Professor, Department of Plant Sciences and Landscape Systems.

8Superintendent, UT Forestry Experiment Station.

9Professor, Department of Animal Science.