"When autumn leaves start to fall..."

Liz West/Flickr

The season goes out in a blaze of glory as the fall foliage colors ignite, but when the party’s over, there’s a whole lot of cleaning up to do.

Leaves become an unnecessary liability as trees enter winter dormancy and no longer need a constant flow of nutrients to sustain themselves. A change in leaf color signals that the end is near and the food factories of deciduous plants are about to be cast aside and set adrift.

When temperatures fall and days shorten, chlorophyll (the green compound that figures  in photosynthesis) breaks down, revealing other pigments present in the leaves. Carotene is responsible for the yellows of the autumn palette, anthocyanins for the reds and purples.

So science tells us, but there are other, more whimsical explanations I rather like. Native Americans, for instance, explain the changing colors of fall with a story about a celestial hunt.

Mighty warriors in the heavens pursued and killed the Great Bear, spilling his blood over the forests – that’s the red of maple, sumac and sassafras. They roasted his meat, dripping fat below – that’s the yellow of birch, hickory and willow.

Notice that this is all about feasting with nary a mention of being knee-deep in litter. A typical forested area drops about 3,000 pounds of leaves and twigs per acre each year, representing a layer as much as six inches deep, researchers say.

Doubtless the natives, lacking leaf blowers and rakes, took the natural approach and just left the leaves where they fell. If your property is wooded, you might do the same. Nutrient-rich leaves eventually will decompose, helped along by bacteria and by worms that emerge by night to recycle organic matter on the surface.

Problem leaves are really the ones that choke the lawn, clog the gutters, pile up on the driveways and smother the garden beds. The Native Americans had none of these modern conveniences and none of the issues with leaves faced by the average suburban homeowner. Lucky them or lucky us?

Color progression   Heather Dawn/Flickr

Perhaps the easiest way to deal with leaf accumulations on the lawn is to skip the raking and blowing and simply mow them in place – my method of choice. A mower fitted with mulching blades is ideal, but even with standard blades, a pass or two will reduce leaf litter to crumbs that will filter down into the sod.

Studies at major universities including Rutgers and Cornell have confirmed that leaving chopped-up, mown-down leaves on the lawn does not hurt healthy turf. The crumbly leaf duff actually improves soil quality, especially on heavy, clay soils.

Ideally, you won’t wait until leaves are shin deep before you start your mowing regimen. Weekly mowing should keep you even with leaf fall, and leave a manageable amount of debris, which will quickly disappear into the grass.

Leaves are also beneficial as amendments to vegetable gardens that you turn over annually before planting, but there is one point to keep in mind. During their first six or eight months of decomposition, leaves produce chemical compounds called phenols that inhibit the growth of seedlings. This process needs to run its course.

Spread leaves on the beds or capture them in temporary bins of chicken wire, leaving them exposed to the elements during the winter. Till them in when the soil begins to warm next April – weathered leaves will have been purged of their phenol and won’t affect spring planting.

Left to their own devices, leaves eventually break down into what gardeners call “leaf mold,” a crumbly, airy soil additive. Some municipalities collect leaves raked or shoved to the curb, carting them off to massive composting operations. But why treat such valuable stuff like garbage? You can just as easily compost your leaves at home.

Roadside leaf piles are slick and slippery in the rain and play havoc with snowplows in years when snowfall comes before the town’s leaf vacuums show up. Leaves also clog storm drains and cause flooding, another traffic hazard.

Parking on leaf heaps should not be done incautiously, especially if you own a sporty, low-slung car. Heat from catalytic converters can set leaves afire, starting a blaze that can consume your little auto. I have seen this happen, and the owner of that particular Beemer convertible was not pleased.

There’s no point in getting annoyed at the annual masses of fallen leaves. Put them to good use and they will seem less like a bane and more like a bounty of fertile, soil-improving stuff – natural, organic and free.