In the garden: Much ado about mulch
August 24, 2009
Everyone who thinks woody mulch in the flowerbeds and heaped around tree trunks in perfect cones makes a garden attractive, please go to your nearest library or bookstore immediately, and check out Thomas Hobbs mouth-watering book, “The Jewel Box Garden.” You will then understand why I find the adjective “attractive” used to describe a garden as inadequate at best and repellent at worst, and also why I think any mulch bought at the store to make your garden more “attractive” is in fact ugly with a capital U. And that’s just the aesthetic consideration, never mind the environmental ramifications or how your plants feel about it.
The idea of mulch has been around since ancient times but the definition of it, its purpose and its composition, has changed considerably and these days is driven more by commercial concerns than by the needs of plants. Peat moss is thankfully out of favor these days for good reasons but chunks or shreds of bark or wood chips are very fashionable. Wood mulch began as a by-product of the lumber industry but burgeoning demand has changed that. The insatiable market for cypress mulch is the leading cause of cypress deforestation, rapidly destroying-permanently- the best protection for our hurricane-prone coastal areas like Louisiana. I thoroughly researched only cypress mulch, but I see no reason to suppose that the horrifying results of our willful ignorance and greed for fashionably dressed gardens is confined to cypress trees.
Is wood/bark mulch good for plants? Most garden writers hedge their bets. Everyone from Co-Operative Extension Services to the International Society of Arboriculturists agree that improper mulching – usually too much – kills trees and there are elaborate rules for proper mulching. For sure, mulch heaped up around a tree trunk in a “mulch volcano,” smothers a tree by depriving it of oxygen. It holds moisture against the trunk, fostering decay and providing a cozy predator-free haven for nibbling rodents who may starve a tree by girdling it. Matted mulch repels water. Decomposing mulch robs plants of nitrogen and compensating with doses of chemical fertilizer just adds insult to injury. The mulch may have allelopathic qualities that inhibit growth and contain pesticide residues or dyes.
Another passionate gardener, Denver’s Rob Proctor doesn’t mince words in “Gardening on a Shoestring”: “People have been brainwashed into thinking that mulching with bark is a good, “natural” thing. There’s nothing natural about it: there’s no ecosystem on the planet where trees shed their bark and uniformly spread it on the ground.” Besides, it looks horrible.