Love moths, butterflies and pollinators? It’s time to rethink your fall leaf cleanup

When we look outside this time of year, we are greeted with one of the most delightful displays of nature’s beauty. I am, of course, talking about the beautiful leaf color on many of our landscape trees in autumn. It is great to see bright hues for a few short weeks here in the metro area. However, the real fun is what happens after those leaves fall.

In the Kansas City metro area, leaf cleanup is considered an essential garden task, especially if your street is lined with oak trees or maples on both sides of the road. In some Johnson County, for instance, leaf cleanup can be a neighborhood event where people help each other clear grass, driveways and sidewalks of plant debris. Although having a tidy yard is important to many people, too much cleanup can hurt our most vulnerable pollinators.

Let’s start with the bees. The U.S. Forest Service points to 49 different species of bumble bees native to the United States, and their populations have declined massively in the past 25 years. These social bees form colonies in underground holes left by rodents or other small mammals.

The queen of these colonies is the lone survivor of the group in the wintertime, and guess where they hibernate? That’s right, under the leaves you are eager to rake up. More specifically, they dig right under the leaf litter in little tunnels. By removing the leaves in the fall, you remove the area where they can hibernate.

Have you ever been outside on a cool morning and seen a luna moth (Actias luna)? What about a viceroy butterfly (Limenitis archippus) visiting your milkweeds that you might have mistaken for a monarch (Danaus plexippus)? These butterflies and many others found in the Great Plains need leaf litter over the winter. Eggs, chrysalis and cocoons may be on the leaves in your yard. Raking them up and putting them in a plastic bag ensures their demise. Mowing over them to create a thatch layer in your grass is also detrimental to the life cycle of these beautiful insects.

Leaf litter can’t be mentioned without bringing up an insect you likely have fond memories of as a child: fireflies. That’s right, fireflies (Lampyridae family) also overwinter in the soil underneath the leaves as larvae. There are around 200 species in the U.S., and just like bumble bees, removing those leaves also removes their potential habitat.

So, if mowing the leaves is bad, raking them into bags and hauling them away is bad, what are you supposed to do to make your lawn look good?

Here are a couple of ideas that you can incorporate into this fall gardening task, and they’ll help you both clean up your yard and provide habitat. First, you can rake them into a neat tree ring around the trees from which they fell. This provides an area of habitat for the insects and benefits the tree by acting as a mulch layer to protect the tree from winter dry spells. Secondly, make a catch-all for all your landscape droppings near a not-so-visible garden area. This can be sticks, logs, grass clippings, and of course, leaves. This technique alone can provide habitat to many different species of insects that we treasure in our gardens.

The decline in native insect populations is a direct result of human activity. You are now equipped to make a positive change. The responsibility to reverse this trend lies with each of us. It’s time for us all to step up and make a difference.

Markis Hill is a horticulture agent with Kansas State University Research and Extension. Need help? Contact the Johnson County Extension gardening hotline at 913-715-7050 or email garden.help@jocogov.org.