Fall leaves can be gorgeous with their vibrant show of color, but they can also wreak havoc on your grass. You can blow or rake the leaves and collect them for pick-up, but consider mulching the leaves, instead, to create beneficial food for your lawn and winter protection for your trees and shrubs.
Why bother with fall leaves at all?
In natural settings, trees rely on the dense blanket of fallen leaves to deter the growth of nearby competition for water and food, choking out plants in their root zone. Similarly, large overlapping leaves will suffocate your grass if left on your lawn during fall and winter.
Even if you have Bermuda or zoyzia grass that goes dormant in the winter, sunlight, air and water are still important for lawn health. Without access to these basic necessities, your grass will be more susceptible to disease and may rot.
Of course you can use this phenomenon to your benefit if you have places in your landscape beds where weeds are a problem. Covering the area with several inches of whole fall leaves can be an effective way to choke out weeds. Just make sure you don’t inadvertently cover any plants you want to keep, like dormant flower bulbs.
Why use leaves for mulch?
Unlike whole leaves, shredded leaves can actually be beneficial to your grass, shrubs and trees. As freshly fallen leaves biodegrade, they leach micro-nutrients like calcium, magnesium, phosphorus and potassium into your soil, benefitting grass and other plants. Leaf mulch is also rich in carbon, encouraging the growth of beneficial microbes in the soil.
Any remaining leaf material helps insulate the grass or other plant’s root zone and protects the soil surface. In fact, according to the University of Michigan, mulching leaves for your lawn for three years can significantly if not completely eliminate weeds like dandelions and crabgrass. The mulched leaf material minimizes propagation by covering the bare spots between turf plants where the seeds from these common weeds would otherwise germinate.
Avoid mulching eucalyptus or black walnut leaves, as they contain elements that can damage other plants.
How do you shred the leaves?
If you have a mulching mower, just elevate the deck to the highest setting and mow, allowing the leaf bits to remain on the grass. You can also use a traditional mower by simply running over the lawn twice in perpendicular directions. Although the shredded leaves will be visible for a few days, they eventually will settle into the grass and provide protection and food for your lawn this winter.
If you have a large volume of leaves, you might opt to bag them every other time you mow and use the collected shreds to mulch in flowerbeds and around the base of trees and shrubs.