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Why to Leave the Leaves

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One of the best decisions that gardeners can make to increase the diversity of wildlife on the land that they steward is to “leave the leaves.”

This easy-to-remember turn of phrase means refraining from raking, blowing, or mowing the fall leaves that butterflies, bees, moths, spiders, toads, salamanders and other critters rely on for habitat to shelter and overwinter in. The benefits are compounded the following spring as pupating insects mature and then emerge as adults, pollinating our plants and providing food for birds and other insectivores.

Our instinct to tidy up our yards in fall is hard to defy, but our local wildlife will be better for it if we can put garden cleanup off until the following spring, after overwintering insects have come out of the leaves. 

Taking it even further, you can leave the leaves permanently in unused areas of your landscape, and let it “go wild.” Plus, the leaves that you do wind up picking up — like leaves on driveways, sidewalks and paths — can be raked or blown into these areas rather than bagged and sent to a landfill.  

 

Yellow fallen leaves under a tree

If we resist the urge to tidy up our yards in fall, our local wildlife will benefit from the habitat and cover that the fallen leaves provide.

 

Why Leave the Leaves?

According to the Xerces Society for Invertebrate Conservation, providing winter cover is “one of the most valuable things you can do to support pollinators and other invertebrates.”

The Xerces Society seeks to raise awareness that though some butterflies are migratory, such as monarchs, most butterflies and moths overwinter as eggs, caterpillars, chrysalises or adults in leaf litter. The same is true of queen bumblebees, which hibernate in burrows that are just an inch or two deep underground and are protected, ideally, by a thick layer of leaves.

On another front, leaf blowers cause noise pollution that can make you unpopular with your neighbors, and their fumes and the dust that they kick up is bad for air quality. Increasingly, towns are banning gas-powered leaf blowers or limiting the hours of operation. You can get ahead of this trend by setting the leaf blower aside and letting the leaves stay where they are.

 

Leaves on the ground under a tree

Consider setting aside the leaf blower this year and letting the leaves stay where they are.

 

Remember that leaves are bountiful in carbon and other nutrients. When we remove every leaf from beneath the tree it fell from, those nutrients are not returned to the tree. 

Leaf litter is a natural mulch that, among other benefits, will prevent freezing and thawing of the soil during winter, which can damage shrubs and other plants, and the following spring the leaves will suppress weeds until you are ready to plant in the area. Leaves also improve the tilth and fertility of soil below as they are naturally broken down by mycorrhizal fungi and turned into worm castings.

 

Fallen leaves at the base of a tree

Leaves provide carbon and other nutrients to the tree from which they fell. (photo: Amy Prentice)

 

The Pollinators That Overwinter in Leaves

There are countless examples of bee, butterfly and moth species that overwinter in leaves. Here are just a handful to give you an idea of the importance of leaves to all insects.

Aphrodite Fritillary – This orange-brown butterfly with interesting wing patterns has one brood per year. The females lay single eggs near violets, the  Aphrodite fritillary larval host plant. The caterpillars that hatch from those eggs overwinter without eating. If the caterpillars are undisturbed and survive the winter, they eat new violet leaves in spring, doing minimal damage that the host plants can easily tolerate.

 

Fritillary caterpillar

Caterpillars of fritillary butterflies often overwinter in fallen leaves. (photo: Amy Prentice)

 

Isabella Tiger Moth – The caterpillar of this moth is a generalist feeder known as the “woolly bear” or “woolly worm.” Eggs are laid in clutches of two or three dozen, and the caterpillars hatch in the fall and then overwinter under leaves. The caterpillars will freeze solid in winter before defrosting and becoming active again in spring.

Red-Banded Hairstreak –  Hairstreaks are a variety of species within the gossamer-winged butterfly family that have slug-like larva. Red-banded hairstreaks, according to the Xerces Society, lay their eggs on fallen oak leaves. Both larvae and pupae overwinter in leaves.

Luna moths – These big, beautiful green moths disguise their cocoons as dried leaves and blend in with fallen fall leaves.

 

Luna Moth

The luna moth is just one of many amazing types of wildlife that disguises its cocoons as dried leaves.
(photo: Amy Prentice)

 

Bumblebee – There are more than 250 species of bumblebee, all in the genus Bombus. Though bumblebees do not form hives like honeybees, they do have queens. Depending on species, bumblebee colonies range in population from about 50 to a few hundred, but only new queens overwinter to start the colony life cycle over in spring. The queens build sites for overwintering in rotting logs or loose dirt and depend on leaves for insulation.

 

wild bees

Bumblebees nest underground, and queens rely on leaf litter for winter insulation. (Photo credit: Amy Prentice)

 

Leaves, Insects and Birds

You may recall that in 2019 the journal Science published a study that showed that since 1970 the bird population in North America has declined by 29% — about 3 billion birds. While habitat loss drives much of the decline in the bird population, another major contributing factor is the collapse of the insect population. 

Insects are a nutritious and vital food source for insectivorous birds and are necessary for rearing their young. Using pesticides indiscriminately or removing insect habitats such as leaf litter reduces the food that’s available to birds.  

We gardeners often think of insects as either pests or beneficials, but there are far more insects that are “neutral” to us and essential to birds. Birds make meals out of insects that emerge from leaves after the winter, and they also pluck insects directly from leaf litter for themselves or for their hatchlings. 

 

Bluebirds with caterpillars

Birds rely heavily on insects and caterpillars to rear their young. Removing insect habitats such as leaf litter reduces the food that’s available to birds. (photo: Amy Prentice)

 

Sourcing Leaves for Compost and Mulch

Leaves provide great value to gardeners as a compost ingredient or organic mulch. If you decide to leave the leaves but still desire compost inputs or mulch, you can do what I do every November: pick up the bagged leaves that your neighbors have put out to the curb.

I collect literally hundreds of bags of leaves this way annually, because as far as I’m concerned, a gardener can never have enough leaves. 

Bagged leaves are often destined for municipal composting operations, but others, sadly, will be sent to a landfill. You can do your part to reduce waste by recycling leaves on your own property — and you’ll save the insects in those bags, too.

 

Joe with bags of leaves

If you want to leave the leaves but still want compost or mulch inputs, you can ask your neighbors for their bagged leaves. I collect hundreds of bags of leaves annually from neighbors — leaves that otherwise might end up in a landfill.

 

In fall, I shred about half of the leaves that I’ve collected. The rest, I store in my leaf corral until spring, allowing the insects to survive.

 

Leaves in a leaf corral

I only shred about half of the leaves that I’ve collected from my neighbor’s bagged leaves destined for the landfill and store the rest in my leaf corral until spring, allowing the insects to survive.

 

Do you “leave the leaves”? Let us know by sharing in the comments below.

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Links & Resources

Some product links in this guide are affiliate links. See full disclosure below.

Episode 134: Bird Population Decline and What Gardeners Can Do to Help

Episode 142: Why Our Plant Choices Matter: Nature’s Best Hope, with Doug Tallamy

joegardener blog: How to Use Fall Leaves in the Garden (And Why You Should)

joegardenerTV YouTube: Why Leaves Change Color in Fall

joegardenerTV YouTube: How to Use Fall Leaves as Garden Mulch

joegardener Online Gardening Academy: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!

joegardener Online Gardening Academy Essential Gardening Fundamentals: The basics on healthy soil, planting, watering techniques, composting, raised bed and other gardening methods, fertilizer, the many benefits of mulch, and more.

joegardenerTV YouTube

joegardener Newsletter

joegardener Facebook

joegardener Facebook Group

joegardener Instagram

joegardener Pinterest

joegardener Twitter

Growing a Greener World® 

GGWTV YouTube

Science study on bird decline

 Xerces Society for Invertebrate Conservation

*Disclosure: Some product links in this guide are affiliate links, which means we would get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us. None of the items included in this list have any bearing on any compensation being an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were 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: Rain Bird, Corona Tools, Milorganite, Soil3, Park Seed, and Exmark. 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.

 

About Joe Lamp'l

Joe Lamp’l is the creator and “joe” behind joe gardener®. His lifetime passion and devotion to all things horticulture has led him to a long-time career as one of the country’s most recognized and trusted personalities in organic gardening and sustainability. That is most evident in his role as host and creator of Emmy Award-winning Growing a Greener World®, a national green-living lifestyle series on PBS currently broadcasting in its tenth season. When he’s not working in his large, raised bed vegetable garden, he’s likely planting or digging something up, or spending time with his family on their organic farm just north of Atlanta, GA.

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