All about leaves
About three weeks ago during the dry spell, I heard what sounded like the rhythm of rainfall. What I saw when I looked through a window was leaves from dozens of trees dropping in a steady symphony of leaf fall. It was not windy, just another morning, but this extended dramatic event of nature was a first for me – leaves across the narrow valley all hearing the same call to action.
Leaves falling in autumn is a good thing for deciduous trees, and it’s not just wind blowing that brings them down. Trees are smart. Maybe they don’t go to Mars, but they know about abscission. As summer wanes, chlorophyll production wanes, and leaves lose their green-making chemistry leaving the yellows, reds, and all the rest. Leaves begin to lose their sustenance because the tree instinctively hardens off the spot where the leaf stem attaches. That way, there won’t be open wounds on tree parts when the leaves fall off.
That hardened group of cells is called the abscission layer. We should refer to October as the Abscission Decision. Trees figured that out without my advice… impressive. And deciduous trees with leaves of any size at all do not need the burden during winter of holding up and sustaining frozen leaves. Limbs would break, and trees know better that. Next spring, they can start all over.
Leaves know from the beginning abscission happens and the wind blows, so they fall and wait for the next thing to happen. It is a personal choice what relationship each of us has with a sudden carpet of leaves. I, for example, enjoy the randomness in the photo-worthy designs in the leaves.
If you keep your yard in pristine, perfect House Beautiful condition all the time, you will want every last interloper on the lawn removed immediately. A mass of leaves might impact a nice lawn, but a few scattered leaves decomposing into the soil is a good thing.
Leaves as they decompose add to the friability and texture of the soil. White oak leaves break down very slowly. They present themselves as unsightly when they collect against a fence or bush, so relocate them neatly as mulch in a bed that needs them. Dry leaves that get crinkled up break down faster.
Out my front windows, I see a wooded area and a smaller cleared area, both covered in leaves. The Leaf Subcommittee of the Front Yard Assembly wrangled itself into and out of knots but reached a satisfactory compromise – the leaves which gracefully fell to the cleared area will be relocated to beds that need them or, secondarily, to the big deal leaf mulch pile known as Shangri-La. The leaves in the wooded area can stay where they fell if they want to.
It is a good idea to use a mixture of kinds of leaves and grassy matter when you mulch. Some materials are more acidic than others and they contribute different elements, and different colors is nice. Freshly harvested tall grassy matter can be cut to size to fit between rows of garlic for the winter. Hickory tree nearby can sprinkle leaves over all of it if it chooses.
In his book The Gardener’s Guide to Better Soil, Gene Logdson devoted an entire chapter to mulch. He states mulch improves the soil’s ability to retain moisture and nutrients plus it adds nutrients naturally. Soil temperatures remain more constant during all seasons under a layer of mulch. He also says working new leaf mulch loosely into the top few inches of soil is beneficial. Use a cultivator to tickle the mulch and topsoil back and forth. After a few seasons of mulching, the soil gets darker, and a gardener can use a tablespoon to scoop down five or six inches.
So, leaves give shade for comfort and color just for fun. Trees drop them down on purpose in autumn, and relocated they make effective mulch and healthier soil. That’s what leaves can do for you.