Running through fallen leaves, crunching them underfoot with that smell of wet earthy goodness assaulting your senses. That is one of the best parts of fall. Once the leaves have fallen and become brown and crunchy they lose some of their visual appeal, but this is when they become even more important for the native insects and the soil microbes.
Leaves become safe places for adult and larval insects to overwinter, and there are still unhatched eggs attached to some of the leaves. Red-banded hairstreaks lay their eggs on Oaks and Sumacs and then overwinter in the leaf litter as caterpillars. Isabella Tiger Moths overwinter as a common caterpillar we all know and love, the Wooly Bear, in the leaf litter. And Luna Moths overwinter in their cocoon within the leaf litter.
Piles of leaves become a place where birds can find food during the lean months of winter. Brown Thrashers, Eastern Towhees, and Gray Catbirds can be found throwing leaves in the air looking for a yummy snack within.
Fallen leaves are also a warm place for many insects and other garden residents to spend the winter. Worms both eat the leaves and take advantage of the insulation they provide to survive cold winters. Spiders take up residence in leaf piles and can hunt through the winter keeping some of the garden pests in check.
If you have left your leaves over the winter and then dug through them the next spring, you might have noticed little white lines running through the leaves. These lines are the mycelium of the fungus varieties that are eating the leaves, breaking them down into usable nutrients for your shrubs, trees, and flowers. There are also vast networks for soil bacteria that help break down nutrients, returning them to the soil for future use.
Even though it might look a bit messy, leaving the leaves for mother nature to use will improve your garden. You will have more butterflies visiting your yard, you will have healthy fungus and bacteria colonies improving your soil health, and you will have great foraging spots for birds. Make this fall and winter a year that you garden for wildlife! Leave the Leaves!!