Aquatic plants play a crucial role in the sustainable management of eutrophic water bodies, serving as a valuable tool for water purification. However, the effectiveness of using aquatic plants for improving water quality is influenced by landscape considerations. In practical applications, challenges arise concerning low purification efficiency and compromised aesthetic appeal when utilizing plants for water purification. To address these issues, this study aimed to examine the impact of aquatic plants on the purification of simulated landscape water bodies, specifically focusing on the effectiveness of the mosaic system of submerged–emerged plants in remediating eutrophic water bodies. Our findings indicated that individual aquatic plants exhibited limited efficacy in pollutant (total nitrogen, total phosphorus, ammonia nitrogen, and chemical oxygen demand) removal. However, when combined in appropriate proportions, submerged plants could enhance species growth and improve the purification efficiency of polluted water bodies. Notably, the mosaic system of submerged–emerged plants neither significantly promoted nor inhibited the growth of each other, but it effectively removed pollutants from the simulated water bodies and inhibited turbidity increase. The comprehensive evaluation ranked the purification capacity as Canna indica-submerged plants combination (C + S) > Thalia dealbata-submerged plants combination (T + S) > Iris pseudacorus-submerged plants combination (I + S) > Lythrum salicaria-submerged plants combination (L + S). Both C + S and T + S configurations effectively mitigated the rise of water turbidity and offered appealing landscape benefits, making them viable options for practical applications in urban landscape water bodies. Our study highlights that a submerged–emerged mosaic combination is a means of water purification that combines landscape aesthetics and purification efficiency.

Vegetation phenology greatly impacts urban development and climate change responses. However, research on phenological characteristics in small-scale urban areas is limited, especially concerning their spatiotemporal variations. This study analyzes the phenological indicators SOS, EOS, and LOS of urban vegetation in Suzhou from 2003 to 2022, utilizing Local Climate Zones (LCZs) and Urban–Rural Gradients (URGs) to explore their spatiotemporal variations and correlations with various LCZs and URGs. Subsequently, one-way ANOVA and the Honest Significant Difference (HSD) test are employed to compare the applicability of the two analytical methods. The results show that in Suzhou, SOS, EOS, and LOS exhibit trends of advancement, delay, and extension, with annual averages of 1.02 days earlier, 0.55 days later, and 1.57 days longer. Compared to land cover types, LCZ built types exhibit earlier SOS, later EOS, and longer LOS. As the urban gradient shifts from the city center to the suburbs, vegetation phenology shows gradually delayed SOS, advanced EOS, and shortened LOS. Additionally, phenological differences associated with LCZs are more significant and statistically relevant than those linked to URGs. The study confirms urbanization’s impact on vegetation phenology and provides new insights for future research. The findings assist in plant management, climate regulation, and living environment improvement, contributing to the sustainable development of resilient cities.