Leave the Leaves Like a Pro
by Eileen Ellsworth
Considerable pressure can be placed on property owners to remove fall leaves. Some HOAs may require their removal. Some neighbors complain if you don’t remove them. Some spouses disagree with each other on what to do.
Wouldn’t it be nice to have a handy, researched based talking point or two when the topic came up? That’s exactly what two scientists working in Maryland have recently handed us.
For two years, Dr. Max Ferlauto, state entomologist for the Maryland Natural Heritage Program, and Dr. Karin T. Burghardt, an ecologist and associate professor at the University of Maryland, studied the effects of leaf removal in residential settings on insects, spiders, and other groups of arthropods.
Leaf litter is critical overwintering habitat for these critters. Thanks to the research findings, we now have data on certain species that make their home among the fallen leaves. In a recent New York Times article on the topic, Dr. Ferlauto was quoted as saying “In a square meter of yard where you leave your leaves, there’s on average almost 2,000 insects that will emerge over the course of the spring.” And that doesn’t include the decomposers like earthworms or millipedes or soil animals called springtails.
He also points out that we can affect overwintering insects in one of two ways. “You could literally be destroying them, or you could be changing their microhabitat such that they don’t survive.”
Their data points are stunning. They discovered that when leaf litter is removed, spring emergence levels for target species dropped up to 45% for moths and butterflies, 24% for beetles, and 67% for spiders! The diversity of moths and butterflies was also reduced by about 40%. High levels of both spring emergence AND diversity are directly tied to the mass of leaf litter we leave in place. The more, the better.
It would be best, of course, if we all let the fallen leaves lie. But that’s not likely. Nevertheless, an “all or nothing” mindset need not rule the day. Here are some thoughtful middle ground suggestions that help improve the ecosystem without bright lines being drawn one way or the other. For example:
· Leave the leaves in the less public “backyard” or “side yard” areas or along less maintained perimeters.
· Leave the leaves on an area of turf you intend to remove come the spring to make way for a new garden bed.
· Leave a 3-5 inch layer of leaves in all gardens and flower beds to provide a natural winter blanket for plants.
· If you have a tree in your yard, rake your leaves under it as opposed to removing them completely. What is best for the critters happens to be also the best for the tree, which is to use the fallen leaves as a natural mulch all the way out to the drip line. Trees do not need and can be harmed by piling up commercial mulch around the base.
We can all agree that some unremoved leaf litter is better than none.
Leaves have fallen in deciduous woodlands for millions of years. Plants and animals galore have come to expect and rely upon the opportunity. As such, every yard management decision across suburban and urban landscape matters. What we plant, how often we water, whether we use pesticides or fertilizers, how frequently we mow, and whether to leave the leaves, all have a huge impact on the local ecosystem.
To learn more, here are some additional articles and reels on the same topic from local groups you may already know and love:
