Those Autumn Leaves – Leaf Them Alone!

Autumn is many people’s favorite time of year, with leaves changing color and the weather becoming crisp, but not yet overly cold.  

Autumn also ushers in one of our least favorite chores: Raking leaves.  But before you start bagging all those leaves up for curbside pickup, two thoughts to consider.

First, those leaves are loaded with the exact perfect combination of nutrients your lawn needs to grow beautifully thick and green.  One of the ironies of the season is those of us with lawns feverishly remove every speck of leaf from the lawn—and then spend too much money on fertilizer, putting back on the lawn the exact stuff we just removed. Silly, huh?

Imagine using a mulching mower instead, and crunching all those leaves into small bits that simply vanish into the lawn, restoring the nutrients the plants need to thrive.  And removing those leaf bags from the trash—and out of the incinerator.

But those leaves do something else for us.  

As autumn slides into winter, insects—the small creatures that hold up the ecosystems that support us—begin dying off.  Each insect species survives the winter in one and only one stage of its life cycle. So tiger swallowtails survive in the chrysalis, ladybugs as larvae, praying mantises and mosquitoes as eggs (and the adult mosquitoes all die—yay!), and the mourning cloak butterfly, unusual for butterflies, surviving as the adult butterfly.  All other phases of the insect dies, so praying mantises and tiger swallowtails disappear, these other phases hibernating.

Right now, insects of all kinds are gearing up for winter, crawling into the nooks and crannies of their habitats for warmer places to sleep for the winter.  Ladybug larvae are in a state of suspended animation: alive, yes, but immobile and almost frozen.  Leaf litter, the decaying remnant of autumn leaves on the bottom of the forest floor, is a hiding place for thousands of hibernating insects.

In our yards, without natural habitat, the fallen leaves in the corners and edges of our properties are the perfect resting places for winter insects.  So removing every scrap of every leaf from every inch of the lawn not only removes the nutrients our trees and grass need to live, but removes the hibernating bodies of the many insects that form the bottoms of food chains. If we want birds with us next spring, we need insects to feed their babies. We need bugs. 

To keep insects around us, keep those leaves.

So as autumn winds and heavy rains knock the quickly-turning-color leaves off our trees, consider a small gift to your lawn and to the natural world. Mulch the leaves onto your lawn, and leave as many leaves as you can tolerate in the nooks and crevices of your property.  Do it for the bugs.  

That tiger swallowtail will thank you. So will I. 

By Mike Weilbacher, Executive Director