Leaf litter has been proposed as a contributing source of excess nutrients found in urban waterways, causing eutrophication and cyanobacterial blooms which affect ecosystem functioning. This study quantified the nutrient leaching rates of crushed and uncrushed leaf litter from two native and two introduced tree species. Leachate testing was conducted in water sourced from a local creek for 168 hours, and samples were taken at intervals to identify changes in nutrient concentrations over time. It was found that crushed leaves had faster leaching rates compared to uncrushed leaves, but concentrations became equal over time. All leaf species leached phosphorus, with the introduced species Fraxinus angustifolia reaching the highest concentration. Nitrogen concentrations increased in one introduced species, but reduced in the other species. These results confirmed leaf litter as a source of external nutrient input, the potential impact of species assemblage on nutrient loads, and the effect of crushing on leaching.