Monday, November 14, 2011

Leaving Leaves Alone

When I was a kid, autumn was always accompanied by the Currier & Ives aroma of burning leaves. Before the age of leaf bags and curbside yard-waste pickup, that's what homeowners did with the huge piles of leaves dropped by their trees.

I miss that smell. But I've come a long way since those days. Besides appreciating clean air in the fall, I've also come to know that lighting a match to leaves is akin torching pure gold.

Fallen leaves contain up to 80 percent of the nutrients that a tree has absorbed during the growing season. If allowed to decay on the ground, they return this store of nutrients to the soil, where they are reabsorbed by roots and channeled back to a new season of growth.

Leaves also are an incredibly rich source of organic matter that helps soil retain nutrients and moisture, while keeping pH levels in balance. And they are a favorite food of those often unsung heroes of the garden—earthworms (which will be covered in Wednesday's posting).

But a season's production of leaves from a single large tree can amount to a formidable pile. And if you live at the south end of a cul de sac, as we once did, a stiff north wind could gift you with most of your neighbors' leaves, as well. (I learned to accept these freebies with glee!)

So how do you manage these mountains of gold?

Flowtron LE-900 with tilt stand
You shrink the mountain.

Shredding leaves can reduce the bounty to 1/16th of its original volume. Shredding also solves another problem: if left whole, leathery leaves such as oak can take years to decompose, meanwhile creating a barrier to moisture reaching the soil.

When it comes to shredding leaves, you have a lot of options, both gas and electric. My sister, who has two large trees in her backyard, simply runs over the leaves with her electric mulching mower. She lets the shredded leaves remain in place, thus eliminating the added chore of raking.

There are any number of gas or electric free-standing shredders—some of the heavy-duty variety also chop small branches, which can be handy during spring cleanup or following a storm. This method requires raking, as well as  stoop labor as you pick up armloads of leaves and feed them into the hopper. But that's terrific exercise almost guaranteed to reduce the waistline.

We use a hand-held leaf vacuum, with a hose that runs to a hood, which fastens onto a garbage can. (You can simply let the leaves blow out the back end of the hood onto the ground, but that makes for a pretty messy situation.) This works most efficiently if the leaves are raked into a pile first, then vacuumed up. But there isn't any stooping.

Patriot Pro-Series leaf vac
Or you could go with a walk-behind leaf vacuum that sucks up and shreds leaves, then deposits them into an attached bag. No raking or stooping—except when clearing leaves from beds.

Of course, if you have a large property with lots of trees, you might want to go with a riding mower with a mulching/bagging attachment. No raking or stooping—or even walking.

So there is a leaf-mulching system to suit just about anyone's pocketbook or energy level.

Once you have your leaves shredded and tidied, you can spread them directly onto garden beds (no more than 2 or 3 inches deep...and rake them in lightly). Or you can corral them in a wire cage or leaf bags for later use, either during winter or during the next growing season.

Shredded leaves make an excellent, nutritious mulch for summer (keeping soil cool while maintaining soil moisture) or winter (piled around tender plants to provide insulation against the cold). Note: you might need to top with a thin layer of cedar mulch, straw, or other weightier material to keep them from blowing away.

Most of all, leaves returned to the soil are able to play their vital role in your tree's great annual cycle of life, from birth to rebirth. 

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