Q. We've tried root mulch, dyed black mulch and other bagged mulches with nothing but problems. What can you recommend?
- ---Bob and Barbara in Chalfont, PA
- ---Maureen in Quakertown, PA
- ---Terry in Doylestown, PA
As I've pointed out many times in the past, most garden centers are going to try and sell you some kind of wood mulch: 'triple premium shredded bark', root mulch or those god-awful dyed mulches—which may contain chipped-up pallets from China, old pressure treated wood, construction debris or other trash. (A little paint can hide a lot.) They push this stuff because: 1) they get it really, really cheap; and 2) it's widely distributed and heavily marketed. The fact that it stains homes, kills plants and attracts pests doesn't enter into their part of the equation.
Unfortunately, they have perfected their selling/marketing of this trash so well that folks like Maureen instinctively put an equal sign between the words 'wood' and 'mulch'. "What can we use instead of mulch" is a constant question in emails sent to the show; and it's the wrong question. 'Mulch'—anything that covers the soil to prevent weeds and retain moisture—is essential; the real question is which kind of mulch will do those jobs without causing any harm. And the answer does not contain the words wood, bark, root or dyed.
To prepare for attempting to deliver a correct answer in a real world format, I visited garden centers. First, I checked out garden sections at the two large nationwide 'big box' home improvement stores. I found no mulch (or product that could be used as a mulch) that I could recommend. Then I sampled the wares at a number of large independent garden centers. Every store had at least one good mulch in stock, sometimes several.
The 'good mulch' I most often encountered was compost; high-quality bulk compost (for delivery) and premium, branded, bagged compost products for smaller jobs. Various 'Coast of Maine' products and Maryland's "LeafGro" compost were the brands I most often encountered at retail, but there were several others that looked equally reliable in the area I haunt between Philadelphia and Washington, DC. Other brand names will predominate at retail in other regions of the country, as these products tend to be somewhat localized. (And, of course, Gardens Alive sells a very nice bagged compost nationwide via mail order.)
Premium bagged composts are more expensive than the big white bags that just have something like 'compost', 'composted soil' or such on them, but they are well worth the extra cost. The branded ones I sampled were fully composted and had a nice black color and very pleasant aroma. The generic ones were often wet, heavy and stinky. (Note: Composted manure is not compost; manure is a fertilizer, not a mulch.)
To use compost as a mulch, spread it one inch to two inches deep on top of your bare soil. University studies have shown that compost mulch prevents weeds and retains moisture just as well as two inches of wood mulch. If your compost mulch gets a little 'crusty' in really dry weather, gently cultivate the surface with a garden hoe. Bonus: Compost mulches will not breed artillery fungus or other nuisance molds, but they will provide all the food your landscape plants require. (You'll find lots more info on using compost as a mulch in this previous Question of the Week.)
Next most available commercially are the seed, nut and hull mulches. Terry mentions cocoa shell mulch, which many gardeners have used with great success. Like chocolate itself, the mulch does pose a danger to dogs that chew everything they see, but otherwise it's close to perfect. (It even has a light chocolate aroma!) Also excellent and attractive are mulches made from pecan hulls, cotton seeds and the like. Peanut shell mulch is great for gardeners in the North—but it's been linked to disease problems in the South. (See this previous Question of the Week for more details.) And pine straw is a great—and very attractive—mulch that's often available bagged and in bulk—especially down South.
But for me, the best mulches are home-grown. If you live in an area with deciduous trees, you really must get a leaf blower/vac and use it to suck up and shred lots of bags of leaves this fall. Shredded leaves make an excellent mulch—and the earthworms that colonize the soil underneath the leaves will feed your plants and aerate your compacted soil for free! (See this previous Question of the Week for more details on how best to manage your fall leaf harvest.) All of the disease prone plants in my landscape—tomatoes, roses, fruit trees, lilacs—are mulched with compost, but everything else gets shredded leaves.
And finally, dried grass clippings from an herbicide free lawn were found to be THE best mulch in a study performed at The Rodale Institute. But those two adjectives are important—the green clippings MUST be air dried until they turn brown before application as a mulch; and they MUST come from a lawn that has not been treated with chemical weed killers. Meet those requirements and you've got the perfect landscape mulch (and, it was judged, the best looking mulch as well).