Ornamental shrubs signifi cantly enhance the service effi ciency of green space ecosystems and the quality of human settlements through their multi-dimensional ecological functions (e.g., microclimate regulation, air pollutant adsorption, biodiversity habitat provision, and soil-water conservation) and landscape aesthetic benefi ts. However, under the infl uence of global warming and accelerated urbanization, the fl owering phenology of ornamental shrubs has shown advances, delays, or disruptions, directly threatening the stability of urban landscape ecosystems. Although Southwest China possesses abundant ornamental shrub species, systematic research on their phenological traits and responses to climatic factors remains lacking, resulting in a lack of scientifi c basis for urban greening confi guration strategies and climate-adaptive management. Therefore, this study investigated 201 cultivated ornamental shrub species in Chengdu Botanical Garden, systematically collecting data on species composition, fl owering phenological traits (including initial fl owering date, end fl owering date, and fl owering duration), and microclimatic variables (temperature, solar radiation, and humidity). Pearson correlation and multiple regression analyses were employed to explore the relationships between fl owering traits and environmental factors, identifying key infl uencing variables. The results revealed substantial diversity in fl owering phenology. The initial fl owering dates (expressed as day of year, DOY) ranged from 20 to 194, while the end fl owering dates spanned 62 to 363. Notably, species from Hamamelidaceae and Malvaceae represented the earliest- and latest-fl owering groups, respectively. The shortest mean fl owering duration (11 days) was observed in Aquifoliaceae, whereas Verbenaceae exhibited the longest (284 days). The fi rst fl owering peak occurred in late April (DOY 110 ～ 120), followed by a secondary peak 10 days later. The highest daily fl owering richness (37.81% of shrubs in bloom) was recorded onDOY 111 (April 20). Correlation analysis indicated that sunlight duration and temperature were the dominant environmental drivers of fl owering variation. Specifi cally, daily fl owering richness showed a signifi cant positive correlation (p ＜ 0.05) with direct sunlight hours, mean daily temperature, and diurnal temperature range, but a negative correlation (p ＜ 0.05) with diff use sunlight hours. In conclusion, this study provides a scientifi c basis for species selection, breeding, and adaptive management of urban ornamental shrubs, while contributing to the understanding of plant phenological responses under climate change.