For many homeowners, fall is the season to rake piles of leaves, bag them up and set them on the curb as yard waste. But in Kalamazoo, more and more people are opting to keep their leaves. Not only do they stay out of the landfill, the fallen leaves provide critical habitat for caterpillars and other bugs.
Unfortunately, the leaves also provide a perfect home for the ticks that carry Lyme disease.
Walking in the backyard of her home in Kalamazoo’s Winchell neighborhood, Donna Keller said that for much of the last 13-years, her family has been restoring their yard to the native Michigan woodland that was here before settlers arrived in Kalamazoo.
“It’s been a fun family project actually. Our son has gotten really into it,” Keller said.
Her son, now in college, grew up working on the yard.
“During COVID, he spent time out here really fixing up the pathways,” she said. “We do a lot of birding back here. We’ve got a great bird list in our yard, 80-some species of birds that we’ve seen or heard here.”
Walking the Keller trails isn’t a stroll through a neatly manicured yard. It’s more like a hike in a national forest where leaves litter the ground.
“So, we don’t remove the leaves. We put mulch down on the paths so that they’re not muddy and not slippery, but otherwise the leaves stay,” said Keller.
This has multiple environmental benefits. For one, Keller's leaves won't end up buried in a landfill, decomposing without oxygen. That generates methane, a potent greenhouse gas helping to drive climate change. And Keller said the leaves also benefit spiders, insects, and worms.
Tom Small agrees with leaving leaves in place. In 1999, Small founded the Kalamazoo chapter of Wild Ones, a group promoting native gardening. Wild Ones encourages homeowners to use the leaves that fall in their garden to nourish native plants that sequester carbon dioxide, help rebuild local ecosystems, and build resiliency to global warming.
“Nature has given you something to give back to the soil. And it’s not chemicals, it’s natural, it’s a gift,” Small said. “Meanwhile you’ve got not just the leaves as a gift, you’ve got insects as a gift.”
While manicured lawns and rakes have hardly gone out of fashion in Kalamazoo, natural yards mulched with their own leaves are gaining ground. Small said in recent years, Kalamazoo Wild Ones has seen its membership quadruple.
But with a new, environmentally friendlier style of yard management, comes a new challenge.
Deer ticks like leaves
“So, we collected a total of 140 ticks in just over 1000 meters here today. Usually, we’ll find about a maximum of 20 at most sites when we drag the full distance.”
That’s Belinda Wilson, Michigan State University research intern with the Midwest Center of Excellence in Vector-Borne Disease. Wilson’s team had just finished dragging for ticks at Kalamazoo’s Kleinstuck nature preserve last May.
They dragged a thick, heavy white corduroy cloth along the edges of the main trail loop, through the leaf litter and the brush.
Disease ecologist Jean Tsao heads up the MSU tick surveillance project tracking ticks in each of Michigan’s 83 counties. Tsao said blacklegged ticks, often called deer ticks, thrive in fallen leaves.
“The issue is that the leaves provide a nice layer that protects the ticks, keeps the relative humidity higher so the ticks don’t dry out, and then they can overwinter,” said the MSU Fisheries and Wildlife associate professor.
Deer ticks aren’t just annoying. As carriers of Lyme disease, they pose a threat to human health. Untreated Lyme disease can cause severe joint pain, arthritis, and potentially fatal heart issues.
The University of Rhode Island’s Tick Encounter website recommends trimming low branches and overgrown shrubs, along with bagging and removing leaves to control deer ticks. While doing this kind of yard maintenance will make it harder for ticks to survive winter in your yard, bestselling nature writer, Douglas Tallamy, said it’s not the best way to control ticks. Tallamy believes that “all the leaves that fall on your property should stay on your property.”
Tallamy is a University of Delaware entomologist who started the “Homegrown National Park” website, a grassroots effort to cut America’s turf lawn area in half by replacing lawns with native plants. Tallamy said that if Americans do this, it would create the equivalent of a 20-million-acre national park, in service of saving local ecosystems and fighting climate change. Tallamy said better deer tick management should target deer.
“Ticks are a problem. I’ve had Lyme disease five times. I get it about ticks. I don’t want to minimize that problem, but we cannot sterilize the earth so we don’t have ticks. The way to do it is to break the life cycle for Lyme disease,” Tallamy said. “So, if you really want to control ticks, you’ve got to get the deer numbers down.”
An ounce of prevention
Jean Tsao, the MSU tick researcher, said people who keep their leaf litter for beneficial insects will harbor ticks as well. But she said with a little care this can be done safely.
“If you can keep the leaf piles further from where you or people are active in their yards, then you should be fine,” said Tsao, who helped develop The TickApp to identify and report tick encounters, along with advise on preventing and removing them.
Donna Keller, who’s keeping the leaves at her house in Kalamazoo, said she knows the ticks are there and she’s careful.
“Worrying about ticks would never prevent me from coming in my back yard and working,” Keller said. “I know that ticks are out here so I wear my insect shield clothing. I’ll tuck my pants in my socks, I’ll tuck my shirt in and wear a hat and those things have served me very well over the years. When I’m finished working, I go straight into the house. I change out of those clothes; I take a shower. I wash those clothes; I dry them in a hot dryer because that helps to kill any ticks that may still be on the clothes.”
And with all that, Keller still checks to make sure ticks aren’t crawling on her. She said with those precautions, the ticks are manageable.