It’s early summer in Rhode Island, and overwhelming the delicate scent of lilacs is the sharp smell of cedar. Well actually, it’s not real cedar, silly, it’s mulch. Millions and millions of square feet of it. Drive into any shopping mall parking lot this time of year and the landscape contractors have likely been by, “refreshing” the mulch in the concrete islands.It wouldn’t surprise me if one of these days, NASA published a photograph from space showing a red swath across much of North America.
So how did this happen? Mulch, when used properly, is a very good thing – in the garden and around trees. It conserves moisture, adds organic matter, suppresses weeds, and makes things look tidy. There are organic mulches, such as straw, wood chips, compost and coco bean hulls, and there are inorganic mulches, like plastic and even recycled rubber.
The choice of mulch is up to you. Just know what you’re buying. Some of the red stuff is not cedar at all, but ground up scrap wood, dyed and perfumed to resemble cedar. There’s even mulch dye you can apply yourself to really freshen things up. Green wood chips can go “sour” as they decompose, damaging plants and even introducing artillery fungus to the outside of your house. Coco Bean Hulls contain theobromine, which is toxic to pets. So choose your mulch wisely.
Applying mulch correctly is really quite simple. Put down just two to three inches, and keep it away from plant stems and tree trunks. And don’t just dump it on your garden year after year just because it looks nice. Anything more than a couple of inches is too deep.
And that brings me to one of my biggest pet peeves, and a major killer of trees: over mulching. The part of the tree that meets the soil is called the root or trunk flare. These tissues need oxygen. If they can’t get it because the tree is standing in water, or the flare is covered in several inches of mulch, the tree will decline and eventually die. When properly applied, mulch is great for trees because it keeps nasty weed whackers from cutting into the bark, and conserves moisture. But the mulch should NEVER touch the truck of the tree, and the flare should always be exposed.
Now, this is the part I don’t get: we know that mulch overuse or “volcano mulching” kills trees. So why do so many landscapers continue to do it? It’s not as though they can’t use mulch at all. They just have to keep it away from the tree trunks.
It’s been a very wet summer so far here in “Little Rhody” and over mulched trees throughout the state are gasping for air.
So please go easy with the mulch. Your garden – and especially your trees – could be drowning.