By Carol Davit, Missouri Prairie Foundation Executive Director
Photo of leaves in native plant bed: Carol Davit.
Through the mastery and mystery of plant chemistry, leaf abscission occurs every fall in woodlands and forests, and petioles detach from deciduous tree and shrub twigs, sending cascades of colorful leaves to the ground.
Hiking through the lower Midwest with crunchy leaves underfoot is an annual delight. Many people love to live in neighborhoods with lots of trees—but instead of enjoying those fallen leaves at home, we tend to go into “yard cleaning” mode.
Why? Because many of us live in houses with canopy and some understory trees on our properties, but with lawn underneath them instead of a woodland or forest floor. A heavy layer of leaves can damage or even kill turf—but are leaves the problem, or is it all that lawn?
Lawns are the perfect vegetation to withstand foot traffic: they are ideal for playing ball in the yard, and perfect venues for barbecues or other outdoor events. If you use your yard for these activities, by all means, leave the lawn where you use it. But for other areas of your property, if the only time you are on your turf grass is to mow it, consider “losing the lawn” and instead, “leaving the leaves.” Converting areas of unused lawn into beds of native wildflowers, grasses, and sedges, as well planting more trees and shrubs, will improve the ecological functionality of your yard and make it more interesting. And when leaves fall in these areas, you can leave them be (althought there are a few natives, like golden groundsel (Pakera obovata) that do best without leaf coverage).
As in forests and woodlands, fallen leaves in yards provide year-round habitat for snails (their calcium-rich shells promote egg strength), insects, and salamanders (which need insects to eat), harbor moth cocoons, and many other animals. Your yard isn’t alive only in summer, but year round, and fallen leaves and other spent vegetation are critically important to many creatures.
Resisting the urge to cut back the stems of grasses and wildflowers at the end of a growing season will also benefit many species. Leaving seed heads and plant structure throughout winter provides continuing food and shelter resources for many creatures and gives people opportunities to observe nature up close. In the dormant season, leaving spent stems of native grasses and wildflowers standing throughout the winter not only gives vertebrate animals shelter, but the stems also are nesting places for native bees. If you trim your native garden or landscaping in late winter or early spring, instead of cutting all spent vegetation to the ground, by leaving 8- to 22-inch tall stems, you will provide nesting areas for stem-nesting native bees. Bees develop in the stems over the course of a year. New growth will hide the stubble.
“Leave the Leaves” signs can be purchased from the Missouri Prairie Foundation/Grow Native! online shop.
[This text previously appeared in slightly different form in the University of Missouri Extension’s Green Horizons newsletter.]