With the fall colors peaking and falling the annual chore of dealing with the carpet of leaves looms in the minds of many homeowners. Leaves are regarded as a nuisance rather than valued for the many benefits they provide.
I once lived in a house surrounded by huge Tulip poplar trees, Liriodendron tulipifera. These trees rained down leaves from late August until early November. We spent multiple weekends dealing with the immense depth of the fallen leaves.
The kicker was once we moved the last tarp full into the woods to decompose, the wind would pick up and blow the leaves from the neighbor’s huge sycamore, Liquidambar styraciflua, into our yard. This would start the process all over again. I fully understand how leaves have been regarded as a nuisance for more than a century in response to the growing reverence for “The Lawn.” As my understanding of natural processes has expanded, my aversion to fallen leaves shifted to acceptance, and I hope this article initiates that shift in your mind, too.
The leaves of a plant are powerhouses of energy. Leaves contain cellular components plants use to capture energy from the sun; does the word chlorophyll ring a bell? In the leaf the process of photosynthesis combines water vapor with the carbon dioxide animals exhale, to form sugar. A plant feeds itself with this sugar, also called carbohydrates.
Think about it, plants are self-sustaining living organisms. Plants are also our best friends forever because another product of photosynthesis is oxygen. I like to raise eyebrows with the fact from the U.S. Department of Agriculture that one large tree can provide a day's supply of oxygen for up to four people. Knowing this, let’s give those leaves a little respect.
The other function of a leaf is to provide food for most of the 158 different caterpillar species found in Virginia. Many of those hungry caterpillars become dinner for equally hungry birds, wasps, flies, spiders, hornets and beetles along with many other insect species. Those baby chickadees born each spring cannot survive without their daily feeding of caterpillars. Did you know that it takes 6,000-9,000 caterpillars to raise one clutch of young, according to Doug Tallamy, Professor, Dept. of Entomology and Wildlife Ecology at the University of Delaware?
Think of the other wildlife relying on leaves to survive during the growing season, these include other insects, deer, rabbits, nutria and muskrats. The bottom line is, leaves are very important to us and other wildlife.
Come fall, leaves take on a whole new purpose; they become either a place to shelter in or a place to forage for food. Many insects overwinter in the leaf litter; some even camouflage themselves as dried leaves to protect against predators, such as birds foraging for insects in the leaf litter.
The Eastern red bat overwinters in leaf litter while millipedes, earthworms, snails and beetles live in the leaf litter year-round. Salamanders use damp leaves as their primary home while squirrels, field mice and birds use leaves to build their nests in trees and piles of brush. Did you know the queen bumblebee hibernates in leaf litter? And here we are raking up all the leaves, stuffing them in bags and removing them from our property every autumn. Come spring, we are then planting flowers with the hope of attracting butterflies and other pollinators to help the environment.
Are you starting to see the disconnect of our actions? I did and I am now a leaf lover. I rake my leaves under the trees to create large circles of organic mulch. This is one of the best practices to adopt.
As described earlier, the leaf litter provides a home for overwintering wildlife. As the layer of mulch kills the grass, the decomposing nitrogen-rich turf feeds the soil microbes, which in turn softens the soil so insects can easily burrow into the soil to overwinter. Best of all, this enriches the soil microbes which dramatically improves the health of the tree.
Take it a step further and create islands of leaf mulch under closely planted trees to eliminate even more lawn creating rich habitat from the soil depths to the tops of the trees. That pretty green lawn is a sterile monoculture with a hard packed soil surface from continuous mowing. Lawns are unwelcoming to native insect pupae trying to burrow into the ground to overwinter while a mulched area under a tree is very welcoming.
Another use for leaves is as a mulch in landscape plantings, but avoid placing them directly against the house because they do retain moisture. Leaves can be used to cover flower beds and vegetable beds, too. This will protect the soil from drying out and being blown away by the wind. These garden areas will benefit from the decomposing leaf litter as it slowly feeds the soil microorganisms over the winter. In the spring your soil will be ready for the new growing season.
Finally, if you have an abundant supply of leaves, offer some to a neighbor who may not have any. Don’t laugh but leaves are valuable to gardeners for the reasons I just shared and for those who compost! A substantial stash of dried leaves is necessary to provide enough carbon, or brown material, to feed a compost pile during the growing season when it is heavy in nitrogen, or green material.
I hope I have turned your thoughts around about leaves as just debris. Just maybe you are ready to turn over a new leaf (sorry, I just could not resist!) and begin seeing the ecological value of the leaves in your yard. They are a gift to be treasured!
Happy Gardening,
Peggy