We investigated the seasonal changes flower color of 163 deciduous woody landscape plants in the Suwon region from January 1, 1992 to March 20, 1993. The results were as follows; 1. By the month of anthesis of woody landscape plants, only one plant of Hamamelis japonica flowered in February, 15 species in March, 48 species in April, 63 species in May, 23 species in June, 12 species in July, and one plant of Hydrangea paniculata was flowered in August. 2. The flowering period was about 220 days from February 24, 1992 that Hamamelis japonica was anthesis to October 5, 1992 when Hydrangea paniculata was deblossomed. 3. By the flowering period of woody landscape plants, 81 species continued for 11 days through 20 days, and Rosa spp., 118 days, Hibiscus syriacus 'Yungkwang', 80 days, Largerstroemia indica, 65 days, and 6 species continued for 41 through 60 days, 10 species were 31 through 40 days, 43 species were 21 through 30 days, and 20 species were for less than 11 days. 4. The woody landscape plants flowering before leaf spreading, Hamamelis japonica, Abeliophyllum distichum, Prunus mume 'Hwahyangmi', Prunus mume 'Baekkaha', Lindera obtusiloba, Cornus officinalis, Prunus armeniaca. The others were plants with leaves spreading white flowering; Forsythia ovata 'Tetra gold', Forsythia ovata, Corylus hetrophylla, Rhododendron mucronulatum, Magnolia denudata, Forsythia koreana 'Seoul Gold', Forsythia koreana, Magnolia stellata, Acer negundo 'Elegans', Magnolia kobus, Forsythia viridissima 'Bronxensis', Prunus yedoensis, Prunus leveilleana var. pendula, Prunus persica for. albiplena, Prunus tomentosa, Prunus persia, Magnolia liliflora, Prunus glandulosa for. sinensis, Cercis chinensis, Poncirus trifoliata. 5. In terms of flower color based on KBS standard color number, 83 species were white, 44 species wer red, 21 species were yellow, 12 species were violet, and 3 species were green. 6. In terms of the flower color by month. Hamamelis japonica was yellow February. Flower colors in March were : yellow-7 species, red-3 species and white-5 species. Flower colors in April were : White-21 species, red-19 species and yellow-6 species. Flower colors in May were : White-36 species, red-16 species. The white flowers in June were 16 species. Flower colors in July were : white-4 species, red-4 species. 7. The white flower color of woody landscape plants of trees was 35 species. The red flower color was 18 species, yellow flower color was 5 species, violet flower color was 2 species, and green flower color was 3 species. Also the white flower color of woody landscape plants of shrubs was 48 species, red flower color was 25 species, yellow flower color was 17 species and violet flower color was 10 species. 8. The new 'Cultivars' of woody landscape plants are needed to introduced the development of planting design. 9. Present data of illustrated books of plants should be checked by new data that was studied in this research.