In the Garden:
The leaves of these deciduous trees and shrubs are potential sources of organic mulch.
Mulches are often described as "silent gardeners" and I totally agree. When properly applied and maintained, mulched areas have fewer weeds, soil temperatures are moderated, water evaporation is slowed, and when you dig them in, organic mulches help improve soil structure.
I don't think it's a coincidence that leaves fall in the autumn to provide a nurturing mulch around plants. Mother Nature has carefully orchestrated this annual event, and I'm taking my gardening cues from her. When we as gardeners apply mulch to our gardens at this time of year, it's simply an adaptation of this natural process.
Advantages of Organic Mulch
While going about its business of keeping moisture in the soil and suppressing weed growth, organic mulches create a rich, unified background for plants, shrubs, and trees.
Mulch lowers the soil temperature in summer and keeps temperatures more uniform, which favors the activity of beneficial bacteria. While plants are dormant, winter mulch reduces injury to roots by moderating temperature fluctuations.
Any mulch derived from living organisms is termed "organic." Shredded leaves, straw, wood chips, pine bark, and loose pine needles will all break down into humus, improving soil structure and providing nutrients along the way. Inorganic mulches, such as black plastic and rubber bark, will moderate soil temperatures and suppress weeds but will not improve the soil. For this reason, I prefer using organic mulches.
How to Apply
Speedy decomposition is acceptable in a summer mulch, but a winter mulch applied now should be sturdy enough to hold up against the elements and provide season-long protection through the winter months. I use maple leaves and pine needles because they're so readily available in my garden and because they're slow to decompose. After cleaning debris from the perennial beds and removing any weeds, I apply a 3- to 4-inch layer of organic material over the soil, taking care not to pack it against plant stems or tree trunks. I tuck it around the crowns of low-growing plants, allowing some space for air circulation. Mulch placed too near a crown may hold in excess moisture and cause the crown to rot.
When to Apply
There are two schools of thought as to when to apply mulch. Some insist mulching should be done before the ground freezes, and others insist it should be done after the ground freezes. I'm not sure it matters much, as long as mulch is applied. But it's not a bad idea to follow nature's lead; mulch in the late fall, just before the ground freezes.
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