In the garden: More ado about mulch
August 31, 2009
A walk along a wilderness trail, be the habitat aspen woods, alpine tundra or desert floor, is a great lesson in mulching. This has been a special year for our native plants and the flowering has been about as good as it gets. All that flowering occurs above a layer of natural mulch shed by those plants; they are in effect self-mulching. The debris on the forest floor isn’t just an untidy by-product; it is a precondition for health. Rake it all up, and the woods and all its biological diversity go with it.
So it seems to me that only local mulch makes sense. Redwood trees are natural to a narrow strip of Pacific coastline less than 500 miles long. How can redwood mulch possibly benefit quaking aspens and spruces on the western slope of the Rocky Mountains? Ditto for cypress trees from the Louisiana swamps, peat moss from northern Canadian bogs, or cocoa hulls from I don’t know where.
However, if a tree or shrub in your yard must come down have it chipped, shredded, and piled in a back corner until it has changed its color and texture and become compost. You can buy compost from the local landfill if you can’t make your own. This is both fertilizer and mulch for your vegetable garden, which is an agricultural, not a natural habitat, and needs much feeding. A thin layer of compost sprinkled in a wide circle around a tree, well away from the trunk, gives you a tidy look if tidy is what you crave, lets you water a bit less, weed more easily, and preserves the tree from machine maulings and stiff competition from grass.
Native or adapted plants don’t need such feeding. Gravel mulch is touted as a necessary component of xeric gardens though my own experiments with it were not notably successful. My stony soil proved to be a boon though. When the understanding dawned that plants boost their chance of survival when protected from environmental vagaries by insinuating their roots among the rocks, my initial resentment at being restricted to planting nothing larger than a seedling evaporated. Letting autumn leaves sift down over my garden and waiting to cut down old foliage and stems until after my perennials and bulbs are actively growing helps too. Then I tuck what clippings I can underneath the expanding foliage, composting the rest. This is garden self-mulching.