Leaves will be coming down like rain next month when the maples, oaks, birches, and other deciduous trees turn color and then shed their foliage ahead of winter. That leads to America’s annual fall raking ritual as homeowners tackle the leafy blanket that ends up on their lawns and in their garden beds.
The traditional view is that all “good neighbors” rake up or blow off the leaves, lest they smother lawns and litter the neighborhood. But there’s another side to fallen leaves… one that values leaves as a rich (and free) resource instead of nature’s trash.
The useful side of leaves
Over winter, leaves make an effective natural blanket to insulate dormant perennials, bulbs, and the roots of young trees and shrubs from winter cold (i.e. free mulch). Added to the compost pile, leaves are a perfect carbon-rich partner for the high-nitrogen ingredients of year-end grass clips, frost-killed plants, and green scraps from the kitchen (i.e. free soil). Worked into the soil, leaves are one of the best materials to break up clay and add moisture-holding ability to sandy soil (i.e. free soil amendment). Left in place to decay, leaves break down into nutritious organic matter (i.e. free fertilizer).
Michigan State University researchers once compared lawns where leaves were mowed and left to decay in place vs. those in which the leaves were raked off. They found that the leaves-on lawns were healthier and better performing, primarily because the decaying leaves added organic matter and nutrition to the lawn.
To remove or not to remove?
Leaves that end up in garden beds can be left in place under and around shrubs, trees, and evergreens as well as on top of perennial beds that are dormant over winter and annual-flower and bulb beds that are bare in winter. Perennials and bulbs can push up in spring through even a two-inch layer of decaying leaves.
For larger pile-ups or for leaves that are covering evergreen perennials or evergreen groundcovers, remove them but don’t bag and discard them. Chop these leaves with a mower (or chipper-shredder if you have one) and use them as mulch over leafless garden beds, add them to the compost pile, and/or save a few bags for mulch under flowers and vegetables next growing season or for amending the soil prior to new plantings.
On the lawn, just mow over the leaves – assuming you’re cutting often enough that the quantity won’t clog the mower or leave behind so many leaf fragments that they smother the grass. Small leaf fragments are beneficial, but you should see mostly grass when you’re done mowing. If you can’t, mow again to double-chop them.
For large quantities of leaves that you can’t mow, rake them, blow them, or vacuum them off so they don’t shut off sunlight to the grass and encourage moisture-fueled fungal diseases such as snow mold. As with excess leaves in the beds, put these leaves to some of the above good uses instead of tossing them.