Too mulch of a good thing
Did you hear about the mulch that spontaneously combusted in Texas last week?
http://www.kvue.com/video/index.html?nvid=166527
That certainly would give a new meaning to mulch volcano!
Fortunately we don’t see too many 100+ degrees days around here, or else there would be a lot of singed sycamores if those ridiculously high mounds of mulch were to ignite.
If you don’t know what a mulch volcano is, just drive around South Jersey and the Philly ‘burbs. You can’t miss ‘em. Pine bark, wood chips, cocoa bean shells - - even shredded tires and stones - - in cone-shaped piles a foot or higher, choking tree trunks and shoveled on shrubs. 
Don’t get me wrong. Mulch is a good thing for the garden. Too much mulch incorrectly placed around trees and shrubs is a bad thing.
Proper mulching reduces erosion, conserves moisture for plant roots and prevents damage from drought, regulates soil temperature, and suppresses unwanted weeds and grasses. Mulches derived from compost or cocoa bean shells add organic matter to the soil.
Besides dressing up the landscape, mulch also protects trunks and stems from getting whacked by power edgers or mauled by mowers.
On the other hand . . .
Mulch volcanoes are a leading cause of disease and death for mountain laurel, linden, spruce, holly, cherry, ash, birch, azalea, rhodos, dogwood and boxwood, according to Rutgers Cooperative Extension and Research.
Mice and voles love to make their homes in thick, cozy piles of mulch. Live tree bark becomes their food source, particularly in winter when the ground freezes making other garden snacks scarce.
Insects use mulch volcanoes as a jumping off point to infest live bark, transporting fungal, viral, and bacterial diseases. Fungi and bacteria thrive on moist decaying mulch. Once established in mulch it then enters bark.
Thick mulch prevents water from getting to plant roots. It suffocates root flares from getting needed oxygen. Mulch volcanoes also promote shallow root development.
A mulch volcano can actually generate enough heat to turn into an active compost pile against a plant stem.
The ill effects of mulch volcanoes aren’t always immediate. Symptoms can include yellowing or muted foliage, abnormally small leaves, or dieback of older branches.
No one seems to know how it began, these piles of wood chips and shredded bark reaching skyward. Over the last several years the slopes have gotten steeper and more common among residential and business landscapes.
It may be horticulturally horrible, yet many find it aesthetically appealing.
Homeowners see mulch volcanoes neatly skirting trees and shrubs of “professionally” landscaped business properties. So naturally they figure if an office building or local bank is paying to have mulch molded into a tall cone around a tree trunk it must be good. Right?
In this case, imitation is the sincerest form of a bad landscape practice.
I spoke to a regional gathering of the New Jersey Landscape Contractors Association this summer. Over slices of pepperoni pizza before the start of the business meeting, I chatted with the boys about the mulch volcano epidemic. I diplomatically suggested they may be setting a bad example for uninformed homeowners (diplomacy is key when the majority of your audience arrive on Harleys or monster-tire pick ups, and sport menacing tattoos on their bulging biceps).
Nobody decked me. They readily admitted it wasn’t proper mulching etiquette. But they can’t stop, they claimed, because their clients will think they are being short-changed on mulch.
It’s a vicious cycle. Can’t blame the guys for trying to please their customers.
Some readers may think I’m making a mountain out of a mulch hill. But the problem is out of control. Heck, one of my Master Gardener gal pals spotted a mulch volcano hugging the base of a telephone pole in Medford!
Fall is the time of year when folks add a little more mulch to protect plants from winter’s harsh extremes. That’s fine. Just follow these guidelines from Rutgers for proper mulching:
• Mulch should be 3” deep or less
• Poorly drained soils less than 2”
• Do not mulch soggy wet soils
• Fine textured mulch less than 2”
• Place mulch on top of soil
• Keep mulch 6” away from structures
• Cocoa bean shells and pine bark mulch (without dyes) are best
• Wood chips should be 1+ years old
• Leaves should be composted for at least 3 months
Don’t use as mulch:
Grass clippings
Fresh saw dust
Peat moss
Fresh from the poop-shoot manure
Rocks or stones
Bricks or pavers
Shredded tires
While you’re out in the yard this fall excavate those mulch volcanoes.
Use an iron rake to pull mulch away from the tree trunk,
3 – 5 inches for young trees, 8 – 12 inches for mature trees. Make a donut of the mulch around the tree or shrub.
It will look good and be better for your plants.
