“Leave the leaves” is a slogan you must have heard by now. Each fall, conservationists encourage homeowners to keep leaves on their property rather than sending them off to landfills. There are a number of reasons to do so, chiefly to support wildlife and reduce contributions to climate change. For a deep dive into why leaving the leaves is such a game-changer, returning to the podcast this week is National Wildlife Federation naturalist David Mizejewski.
David holds a degree in human and natural ecology from Emory University and is an expert on wildlife and the environment. He’s dedicated to using his knowledge and unbridled enthusiasm to help others understand and protect wildlife. He hosted and co-produced “Backyard Habitat,” a television series on Animal Planet that showed people how to transform their yards and gardens into thriving habitats for birds and other wildlife. He’s also appeared in the Animal Planet miniseries “Springwatch U.S.A.” and on Nat Geo Wild in series such as “Are You Smarter Than…”, “How Human Are You?” and “Unlikely Animal Friends” and co-hosted the network’s prime-time television series “Pet Talk.”
David says that in his 24 years at National Wildlife Federation working in conservation, he has seen the needle move toward sustainable gardening. When he started out in 2000 and asked a crowd if they know what a native plant is, most people didn’t know what he meant. Now, most people raise a hand.
Conservationists have also made progress on raising awareness of the importance of leaving the leaves. Not only does it support wildlife and reduce pollution, leaving the leaves also means free mulch and fertilizer. To raise awareness further, for the second year, National Wildlife Federation has designated the month of October as Leave the Leaves Month.
David says we, as gardeners, can be part of the bigger picture conservation movement just by making choices on how we take care of our own little piece of the Earth — our yards, our landscapes, our gardens.
People who care about nature or the environment or climate change have banded together relatively quickly, in a matter of a few years. People used to approach those of us in the industry and ask, regularly, “What can I spray on this to kill it?” These days, that question doesn’t come up. Gardeners have evolved to seek out solutions that minimize negative impacts on wildlife.
Leaves Are Not Trash
Knowing what I know now, I can’t look at a paper sack of leaves anymore without recognizing all the life that’s in that bag right there. I know it’s not trash in that bag.
My favorite mulch is shredded leaves. I love it so much, I actually bought another leaf shredder a few years ago so my daughter and her boyfriend could shred leaves I collected while I ran my own shredder.
All of November, we’d spend the weekends shredding, and I’d post on Nextdoor and Facebook in local community groups, asking neighbors to give me the leaves they didn’t want rather than send them to a landfill. I would typically collect 300 to 500 bags full of leaves. The shredded leaves would go into a massive corral for use in my vegetable garden the following spring and my native plant areas. It was free mulch, and it was the best mulch.
Then I began hearing from conservationists such as Doug Tallamy about the importance of leaving the leaves. I prioritize being ecologically minded, so I weighed how I can still use my shredded leaves and do the right thing.
I am now at the point where I just leave the leaves for the most part. I shred 20% of the leaves that I collect for my mulch needs, and the other 80% I use whole in my native garden beds.
That’s my compromise to myself, though I still struggle with that because while I feel good about saving leaves from a landfill, I am still shredding some, which is not great for wildlife.
Fortunately, David helped me cope with my guilt.
“What you are doing is absolutely 100% okay to do,” he says.
“We are all on this journey of sustainability together, and I am not going to be here preaching to you and making you feel bad about anything good that you’re doing,” he says. “Think of it as sort of a continuum of things that we can be doing. At the far end of the continuum, the thing that is most natural to do — the thing that happens in nature — is to let your leaves lie where they fall. But guess what? That’s not reality for most.”
I collect bags of leaves that otherwise would have ended up in a landfill. They are the bets mulch — and free.
The National Wildlife Federation completed its second annual Leave the Leaves survey and found:
90% of those surveyed are willing to leave or repurpose leaves to benefit wildlife and the environment; however
52% of people are required to rake their leaves by either a homeowners association, a city ordinance, or a combination of both
53% said they currently repurpose raked or collected leaves for mulch or compost
23% of people said they throw away between six and 10 bags of leaves in the trash per year
11% said they dispose of more than 10 bags of leaves per year in the trash
15% of people actually leave their leaves in their yard
David says at one end of the spectrum is leaving leaves right where they fall, and at the other end of the spectrum is raking or blowing all of those leaves, putting them in bags and sending them to the landfill — a really horrible thing to do for many reasons.
Most homeowners fall somewhere in the middle, because most have a lawn — though some have less lawn than others.
“Even I have some lawn,” David says. “I don’t put pesticides on it, I don’t fertilize it, I don’t water it, et cetera. But it’s where I play fetch with my dog and where when my niece and nephew come over, we kick the soccer ball around. That’s okay.”
When he removes leaves from his patch of lawn, he relocates those leaves to planting beds as natural mulch. “That’s the main thing the National Wildlife Federation is recommending,” David says.
Some people will follow this practice but have more leaves than their beds can accommodate.
“If you wanna shred some of them, absolutely, that’s fine,” David says. “Yes, you’re going to be chopping up some of the wildlife, some of the Lepidoptera — the butterflies and moths that are overwintering in there — but look, if it’s 20% and you’re saving 80% whole, you are doing more than probably 80% of people out there.
“So, do not feel guilty for a second because that leaf mulch, or that leaf mold that forms when you compost shredded leaves, is indeed incredible mulch and fertilizer.”
Large windrows of compost at a municipal composting facility. Some municipalities will collect leaves and other yard waste for composting, but unfortunately, many municipalities will just send leaves to a landfill as if leaves were trash.
Big Reason to Leave the Leaves: Wildlife
There are three main reasons why leaving the leaves where they fall, or at least retaining them on your property, is valuable. At the top of the list for the National Wildlife Federation is to ensure wildlife has good habitat.
“If we plant native plants and we don’t spray pesticides, we can actually invite in all of these incredible wildlife species that can safely coexist with us — songbirds, butterflies, other pollinators, et cetera,” David says.
One of the key parts of gardening for wildlife that hasn’t gotten as much attention, he says, is the importance of the natural leaf layer as wildlife habitat.
There are many species that rely on the leaf layer for at least part of their life cycles.
“The leaf layer is filled with all sorts of invertebrates,” David says.
Earthworms, for one, eat decomposing leaves and turn them into worm castings, which is a valuable fertilizer. Pill bugs likewise break down leaves, and they detoxify soil by removing heavy metals.
Fireflies, also called lightning bugs, are neither flies nor bugs. They are beetles, and their larvae overwinter and pupate in and under the leaf layer.
Some wild bee species rely on the leaf layer, notably bumblebees. Next year’s bumblebee queens seek shelter in little boroughs on the surface of the soil, underneath the fallen leaves. “Those fallen leaves provide insulation for them so that they can actually survive the winter and emerge in the spring and start next year’s bumblebee hives,” David explains.
The rusty patch bumblebee is the first bee in North America to be listed as an endangered species, and Franklin’s bumblebee recently joined the list. The western bumblebee and the American bumblebee are also declining.
Lepidoptera — butterflies and moths — are very reliant on leaf litter. The vast majority overwinter as either caterpillars or adults in leaves.
Caterpillars are an essential baby bird food. They are a primary food source for the offspring of 96% of our backyard birds. Birds as varied as woodpeckers, nuthatches and hummingbirds feed insects to their young.
“When you bag up and throw away your leaves, you are wiping out entire generations of really important pollinators — the bumblebees and the moths and the butterflies,” David says. “And you are robbing the bird population next spring of the food source for their babies. It’s no wonder we’re seeing pollinator declines. And it’s no wonder that the North American bird population is down.”
The eastern red bat is another animal that needs the leaf layer. Found over a wide swath of eastern North America, the eastern red bat overwinters under leaves when temperatures are subfreezing.
A spotted towhee two-stepping through the leaf litter. Birds search leaf litter for insects to eat and to feed their young.
(Photo Credit: bgwashburn, licensed under CC BY 2.0)
Big Reason to Leave the Leaves: Climate Change
Each year, 10.5 million tons of yard trimmings, a major portion of which is fall leaves, end up in landfills. Landfills are the third largest source of methane production in the United States.
When leaves are bagged up and sent to a landfill, they get buried underground. Because there is no oxygen down there, the leaves break down via anaerobic decomposition. This creates methane, a potent greenhouse gas that traps heat in the atmosphere.
Leaves that are composted at home break down in the presence of oxygen and don’t produce methane.
“You have free mulch and fertilizer provided by Mother Nature,” David says. “Why on earth would you waste all of your weekend in the fall raking or blowing leaves, and then throwing them away, and then turning around and going to the store and buying mulch and fertilizer? It’s actual insanity, right? So leave the leaves on your property because it’s free and it’s easy, and it’s the right thing to do.”
Even people who are not interested in combating climate change can adopt leaving the leaves as their norm just for the sake of saving time and money.
Leaves brought to a landfill decompose in an anaerobic environment and give off the greenhouse gas methane. (Photo Credit: David Mizejewski)
Yard Doesn’t Have To Equal Lawn
For many people, yard equals lawn. That’s because of how “Big Garden” has trained us to think about our yards.
When the National Wildlife Federation says “leave your leaves,” they don’t mean on your lawn. A thick layer of leaves would kill your lawn. They mean leave your leaves someplace on your property rather than sending them away to a landfill.
Of course, reducing your turfgrass lawn by converting it into valuable wildlife habitat is something you should seriously consider. Lawns require water, fertilizer and herbicides, not to mention mowing, which creates noise and uses fossil fuels. And lawns are wildlife dead zones.
“Let the leaves fall on part of your lawn and turn it into a new garden bed that you can plant good native plants that are going to be beautiful, and they’re going to be functional, but they’re also going to support wildlife,” David says.
You can minimize the wild look by adding edging around the bed and adding a “human element” like a birdbath.
Don’t think of “lawn” when you think of your yard. A leaf mulch bed is an ecologically valuable addition to a yard. (Photo Credit: David Mizejewski)
Make a New Garden Bed for Keeping Leaves
David offers a challenge:
“This fall, make one new garden bed, 5 by 5, 10 by 10 — whatever it is — and just pile a good layer of leaves.” He typically recommends anywhere from three to five inches.
Use the leaves just like any other kind of mulch, like shredded hardwood or bark chips or pine straw. The leaf layer should be enough to suppress weeds and retain soil moisture but not enough to stop herbaceous perennials from coming back in spring. And don’t pile leaves against the trunks of woody plants.
Too much mulch can also make it hard for water to reach the roots of plants.
“With fallen leaves, maybe put them on a little bit thicker than you would a store-bought mulch simply because they’re delicate and they are going to break down pretty quickly, and so they’re going to shrink a little bit.”
How fast the leaves break down will depend on the kinds of trees the leaves come from, where you live and what your landscape conditions are. The leaf layer should be adequate to last through the fall and winter and into spring, when plants are leafing out again. By mid-April, most of the leaf mulch will have broken down and returned nutrients to the soil.
Remember that some leaves, like oak leaves, are tough, and will take much longer to break down than maple leaves.
Designate an area in your yard where leaves can go that doubles as a planting bed. (Photo Credit: David Mizejewski)
“Another 25 years from now, I think we’re going to make exponential leaps forward, but it takes us, now, committing to it and taking the actions and spreading the word and being a force for positive change,” David says.
I hope you enjoyed my conversation with David Mizejewski on the leave the leaves movement. If you haven’t listened to the podcast yet, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
Do you leave the leaves? Let us know how in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
Episode 071: Gardening for Wildlife: How to Create an Inviting Habitat, with NWF’s David Mizijewski
Episode 126: Using Leaves as Mulch & Compost (and Why Leaves Change Color & Shed)
Episode 134: Bird Population Decline and What Gardeners Can Do to Help
Episode 206: Our Most Essential Trees: The Nature of Oaks, with Doug Tallamy
Episode 262: Garden for Wildlife: Accessing the Right Native Plants, with the NWF
Episode 261: All About Native Bees, with Heather Holm
joegardener blog: Why to Leave the Leaves
joegardener blog: How to Use Leaves as Garden Mulch
joegardener blog: How to Use Fall Leaves in the Garden – and Why You Should
joegardenerTV YouTube: Leave the Leaves and Seed Heads to Support Overwintering Wildlife
Master Home Composting: Learn how to turn your food scraps and yard waste into nutrient-rich compost in my Master Home Composting webinar presentation! Join me on Wednesday, October 23, at noon Eastern.
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course. The course is designed to be a comprehensive guide to starting, growing, nurturing and harvesting your favorite vegetables, no matter what you love to eat, no matter where you live, no matter your level of gardening experience.
joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier.
joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
Attracting Birds, Butterflies, and Other Backyard Wildlife” by David Mizejewski
National Wildlife Federation: National Leave the Leaves Month
Naturalist David Mizejewski on Facebook
David Mizejewski on Instagram | @dmizejewski
David Mizejewski on X | @dmizejewski
David Mizejewski YouTube Channel
Certified Wildlife Habitat Program
National Wildlife Federation Facebook
National Wildlife Federation Instagram
National Wildlife Federation Twitter
Milorganite® – Our podcast episode sponsor and Brand Partner of joegardener.com
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast was based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Corona Tools, Milorganite, Soil3, Greenhouse Megastore, Territorial Seed Company, Earth’s Ally, Proven Winners ColorChoice, Farmer’s Defense, Heirloom Roses and Dramm. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.
