Each autumn, millions of tonnes of leaves fall to the ground. While the reflex for many gardeners is to dispose of them, leaving leaves in place provides enormous benefits, supporting invertebrates, enriching soil and capturing carbon.
Research shows the extent that garden biodiversity that depends on leaf litter. In a two-year study conducted across 20 pesticide-free gardens, researchers showed that raking up autumn leaves decreased the abundance of spring emerging arthropods by 17%, and reduced Lepidoptera species richness by 40% and abundance by 45%. Beyond invertebrates, fallen leaves provide great benefits to soil itself. As leaves decompose, they break down into organic matter that enriches soil structure and fertility, improving moisture retention and reducing the need for chemical fertilizers. This process creates an ideal environment for beneficial microorganisms and fungi that further support plant growth. Leaf litter also acts as a natural mulch, regulating soil temperature and moisture while inhibiting weed growth and preventing soil erosion. Another benefit of leaving leaves involves carbon capture and storage. Research comparing areas with retained versus removed leaves demonstrates measurable differences in soil carbon accumulation. Areas where fallen leaves are regularly left in place show up to 32% more soil organic carbon compared to areas where leaves are regularly removed.
- Selective retention: Leave leaves in less visible areas such as at the back of beds and under trees where they provide habitat while maintaining a tidy appearance.
- Light layering: Research confirms that a light layer of leaves (less than 20cm) decomposes by spring without smothering grass.
Leaf piles: Create small piles or windrows in a corner of the garden. These habitat piles are particularly beneficial while preserving space elsewhere. - Mulching: Leaves can be used as mulch around garden beds, providing insulation, moisture retention, and habitat benefits while maintaining a smart appearance.
- Delayed cleanup: Postponing garden cleanup until spring allows insects relying on leaves for winter shelter to safely emerge as temperatures warm.
By leaving leaves in place, gardeners can support invertebrate populations that sustain entire food webs. This is particularly important because many bird species, especially songbirds, depend on caterpillars as their primary food source for raising young, and those caterpillars depend on overwintering leaf habitat. Fallen leaves are not waste, they are essential ecological infrastructure. Sometimes the most ecologically productive action you can take is to do nothing at all.
Ferlauto, M., & Burghardt, K.T. (2025) Removing autumn leaves in residential yards reduces the spring emergence of overwintering insects. Science of The Total Environment, 970, 178821. https://doi.org/10.1016/j.scitotenv.2025.178821
Ferlauto, M., Schmitt, L., & Burghardt, K. (2024) Legacy effects of long‐term autumn leaf litter removal slow decomposition rates and reduce soil carbon in suburban yards. Plants, People, Planet, 6(4), 875-884. https://doi.org/10.1002/ppp3.10499