Study on smellscape perception and landscape application of fragrant plants

Plants in parks emit different fragrances. How will these fragrances affect us? How can we better allocate these plants? In this paper, five kinds of traditional fragrant plants in northern China were selected for fragrance analysis by gas chromatography-mass spectrometry (GC–MS) and the fragrance types and diffusion process were analyzed by a smell-walking method. Subjective evaluation of fragrance perception was carried out in outdoor plant communities using a semantic differential method. At the same time, the application of fragrant plants was discussed. The purpose was to explore the relationship between smellscape and perception and provide a reference for smellscape map drawing and landscape application of fragrant plants. Study plants were shown to plants present different fragrance types: monoterpense, syringaldehyde, β-ionone and acetic acid phenylmethyl ester were the main compounds of magnolia, syringa, osmanthus and wintersweet, and linalool was also the major compounds of tree peony, osmanthus and wintersweet. Smell-walking survey reported that magnolia and tree peony exhibited a woody and light medicinal fragrance, syringa emitted a powerful hyacinth-like odor, osmanthus had a strong sweet smell, and wintersweet had a fresh sweet smell. And subjective evaluation of fragrance perception was positive; the evaluation value of osmanthus was the highest, followed by magnolia and wintersweet, and finally syringa and tree peony. Further, subjects found tree peony to be less pleasant because of its mixed fragrance. We also found that fragrance concentration and diffusion were related to plant density, tree height, receptor location and spatial range. Other factors, such as surrounding plants, landscape architecture, rockery and water also affected fragrance diffusion. Our findings show that these myriad factors should be considered comprehensively in plant allocation.