Why – and How -- to Leave Your Leaves
Less work for you means more benefits for nature
Ecologically speaking you do not need to rake leaves, but a heavy layer can smother your lawn grass and prevent new growth in spring. Compacted leaves can promote snow mold diseases that damage turf grass. The easiest way to treat leaves on your lawn is to pass over them with a mower a few times to shred them into small pieces. This method will return nitrogen to the soil as the chipped leaves decompose.
In the garden, you can leave them where they fall, so they help insulate plant roots. You can rake them and run them over with the mower, then return the shredded leaves to the flower beds or around shrubs and trees. This layer of leaf litter provides vital cover for overwintering insects. Protecting insects during the winter in turn provides more nourishment (think caterpillars) for birds when raising their young in the spring.
If you want to remove leaves from your garden, add them to your compost pile rather than bagging them and hauling them away. Composting leaves is a great way to recycle nutrients.
When possible, it’s valuable to allow some leaves to rest undisturbed where they fall in naturalized areas of your lawn. This provides the greatest protection and least disturbance for the variety of birds, toads small mammals and other creatures.
Adapted from: Fall Garden Tasks, Penn State Extension