The combined pollution of heavy metals and polycyclic aromatic hydrocarbons is very common in China and needs urgent addressal. The use of resistant garden plants for phytoremediation accounts for both ecological restoration and ornamental value and has great application potential. In this study, cadmium (Cd) and pyrene (Pyr) were used as contaminants, and the growth responses, enrichment characteristics, and physiological responses of common garden plants were studied using greenhouse pot experiments. The Cd-Pyr compound stress affected the growth responses of plants. Chinese Pennisetum and lotus exhibited the best Cd-Pyr removal effect: the removal rates of Cd were 68.91% and 60.25%, respectively, and those of Pyr were 77.52% and 63.74%, respectively. Compound stress promoted the protective enzymes of ryegrass, lotus, and Chinese Pennisetum. Malondialdehyde (MDA) content in the leaves of the five plants was higher than that in the control group, whereas the chlorophyll and carotenoid content were lower. Overall, the order of resistance of the five garden plants tested under Cd-Pyr compound stress was: Chinese Pennisetum, lotus > ryegrass > Hemerocallis, Purple Coneflower.

With the acceleration in urbanization, surface hardening has increased, urban flooding and soil erosion problems are frequent, and urban water resource management faces great challenges. Sponge city construction can effectively alleviate these problems by simulating the natural water cycle and constructing blue–green infrastructure. In this study, the analytic hierarchy process (AHP) and the ArcGIS weighted overlay tool were used to construct a framework for assessing the suitability of sponge city construction in Suzhou from the three dimensions of Geo-Smart spatial productive forces, Eco-Dynamic green productive forces, and Resilio-Tech responsive productive forces. A zoning strategy based on new quality productive forces is also proposed. The results show that Suzhou can be divided into three types of construction zones according to the suitability level: key construction zones, secondary key construction zones, and general construction zones. The key construction zones account for about 28.01% of the total land area, mainly covering the built-up areas of Suzhou, covering the developed urban areas such as Gusu District, Xiangcheng, Suzhou Industrial Park, and other key zones such as Northern Kunshan. The secondary key construction area and general construction area, on the other hand, account for 61.94% and 10.05% of the total area, respectively. From the new quality productive forces, this study proposes the following construction guidelines for sponge city zones: (1) enhance the coordinated development of urban planning and sponge city construction; (2) promote blue–green infrastructure development, strengthen inter-departmental cooperation, and ensure ecological and economic co-development; and (3) encourage public participation in governance. This research offers theoretical and practical guidance for sponge city construction in Suzhou and other cities from the perspective of new quality productive forces.