Objective  Ornamental property of various Hydrangea paniculata, the few increasingly popular flowering woody plants that blossom in summer, were studied for the development, utilization and breeding of new varieties.

  Method  Fifteen phenotypic characteristics on the branches, leaves and flowers of 17 varieties of H. paniculata were examined for a systematic analysis and classification.

  Result  The morphological variations among the varieties were generally minute, with a coefficient between 0.88% and 5.66% on florets, between 0.88%~8.58% on branches and leaves, and between 2.08% and 14.83% on inflorescence. The flowering lasted 23 d to 54 d. The correlations between inflorescence transverse diameter (x₁) and volume of inflorescence (x₅) had a coefficient of 0.929, between inflorescence longitudinal diameter (x₂) and x₅ 0.752, between color of a flower after it changes color (x₉) and color of aging branches (y₆) 0.777, and between leave length (y₁) and leave width (y₂) 0.882. Based on the characteristics, the 17 varieties could be clustered into 2 to 5 categories.

  Conclusion  The branch, leaf and flower phenotypes of the 17 varieties of H. paniculata differed to varying degrees, with the inflorescence being the greatest. The correlations among the characteristics were significant between x₁ and x₅, between x₂ and x₅, between x₉ and y₆, and between y₁ and y₂. The information would be of value in genetic studies on H. paniculata, as well as, in selecting, developing and utilizing superior new varieties.