Poplars and willows have been cultivated for their environmental benefits for millennia. In the present study, physiological responses were examined in three poplar and three willow clones grown in soil from the landfills near Novi Sad and Belgrade, Serbia. The experiment, conducted under controlled conditions in pots with soil directly from the landfill sites, aimed to identify the most suitable clones based on their physiological performance on examined substrates. Within the process of phyto-recurrent selection, six clones were selected for this experiment: Populus deltoidescl. PE 19/6, PE 4/68, S 1-8, and Salix alba cl. 107/65-9, 79/64-2, 380. Four physiological parameters (net photosynthesis [A], transpiration [E], water use efficiency [WUE], and stomatal conductance [gs]) were measured throughout the research. Analysis of variance revealed that certain clones exhibited superior physiological responses compared to others. The superior performance of poplar clones PE 4/68 and S 1-8 in key physiological parameters underscores their potential for improving growth, resilience, carbon sequestration, and overall ecological and economic benefits, making them valuable candidates for forestry and environmental management programs.