Tree Talk: Leave the leaves
October 17, 2022
It is part of the Autumn Ritual: Harvest the last of the vegetables and clean up the garden. Mow the yard, one last time before winter. Rake/mow/blow the leaves – but what to do with all these leaves?? If you have an open yard, North Dakota's wind may take care of most of the leaves and share them with
a neighbor. Most homeowners take great pride in their homes and yards and invest time and energy to keep things tidy. (A 2005 NASA study estimated around 40 million acres of lawn in the continental U.S. – making turfgrass one of the largest "crops" we grow. Wow!) A thick layer of leaves will smother lawn, which is the reason we should not let them accumulate. However, a thin layer of leaves left on the lawn can be chopped with a mulching mower and will add organic matter to the soil. Leaves are free fertilizer.
Instead of raking and bagging leaves to be disposed of in a landfill, use the leaves as mulch for flower beds and around the base of trees to protect plant roots. Use a trash can to fill with leaves and chop them with a hedge trimmer for a fine mulch that is less likely to blow away. While we might have enjoyed the lack of snow last winter, many plants – especially young trees and perennial herbaceous plants - suffered root injury due to frigid temperatures and the lack of an insulating snow layer. Use leaves as an organic mulch to insulate roots.
Fallen leaves are important habitat for wildlife, including multitudes of small critters that are essential for a healthy ecosystem. Monarch butterflies famously migrate south to overwinter in sunny Mexico. Other butterfly and moth species, many of which are pollinators, overwinter "at home" in the leaf layer – a few in adult form, but others as pupae, larvae or eggs. Birds forage in the leaf layer to search for insects and other invertebrates to eat. Nearly all backyard bird species rely on butterfly and moth caterpillars as the primary food source for their babies during the nesting season. If you remove all the fallen leaves, there will be fewer of these insects in your yard and fewer birds, too. Even some bat species overwinter in the leaf layer and can't survive severe cold temperatures without cover. Suppress the "eek!" impulse and keep in mind that a bat can eat 600 to 1,000 pesky mosquitoes and other insects in one hour. Leaves provide habitat for wildlife.
If you feel more ambitious, create a compost pile in a corner of the yard. Combine fallen leaves ("brown material") with grass clippings and other "green material". With a bit of practice and patience, your prize is nutrient-rich compost to add to the garden.
Don't feel obligated to get rid of every leaf in the yard this fall. Wait till spring to remove the leaves piled as a protective mulch. Leave the leaves - they provide many benefits for wildlife and your garden.