Classification of shrubs for textural groups: a landscaping perspective

Abstract

Landscaping provides an alteration to the existing designs where technology blends with natural surroundings ensuring functional, ecological and aesthetic aspects in which plants play an important role. The physical characteristics of plants particularly the texture is an important attribute mostly misinterpreted and underutilized in Sri Lanka due to the lack of information on different textural groups of plants. Hence, the objective of this study was to investigate the morphology of commonly used shrubs to elucidate their texture in the view of promoting the incorporation of plant texture in landscape designs. Thirty shrub species, including 24 commonly used and six with a potential to be used in landscaping were selected. Quantitative morphological characters viz., leaf margin, arrangement, leaf surface and prominent venation, presence and type of hairs on upper and lower surfaces of leaves and on petiole and qualitative morphological characters viz., internodal length, petiole length, hair density, hair length and leaf area were studied subjecting the results to hierarchical cluster analysis. The study recognized three distinct textural classes representing 16 fine textured, six medium textured and eight coarse textured species to be blended in planting designs. The fine textured plants exhibit a contrast feeling when they are blended with coarse textured plants where medium textured plants fulfil the design by providing the linkage between the fine and coarse textures. Further, these textural groups could be used in creating garden illusions. Plants with unique textures make the design more attractive and enhance the visual interest. Due to their unique morphological characters, the coarse textured plants are capable of intercepting particulate matter present in air effectively. Hence these plants could be promoted to reduce air pollution. Therefore, the present study would enable the practitioners to incorporate the planting materials more worldly into the landscape designs bringing the aesthetic and environmental benefits on stage.