Wood Mulch is Not as Helpful as You Think

Folks, the industry has us a bit duped on wood mulch. Here are some thoughts seeing as we constantly get bombarded with the benefits / necessity of wood mulch:

1) Wood mulch improves soil? Sure, a little, over time, nearer the soil surface. Know what does a lot better job and you don’t have to re-apply it every year to keep getting soil amending benefits? Plants. Plant roots. Via plant density. Green mulch. There’s a reason the corn belt sits on top of the former tallgrass prairie.

2) Wood mulch prevents weeds? A little, yes, sure, ok, but if you dump 4-6+ inches you are actually creating an ideal germination bed for weed seeds to root out into as it’s moist, lots of air, etc.

We apply just 1-2″ of wood mulch one time on a new garden install for two reasons: 1) to slightly reduce annual weed seed germination as clients are DIY managers and 2) to show intention to neighbors (most folks think mulch = good garden design or maintenance). We do NOT apply a fresh layer every spring and neither should you because:

WOOD MULCH KEEPS PLANTS IN A PERPETUAL STATE OF ESTABLISHMENT.

(Also, you can’t seed into wood mulch. A lot of folks ask about this.)

Put down too much mulch and it takes years to break down, years in which desirable plants can’t self sow, give you free plants, fill in, compete against weeds much better than wood mulch, and provide so many more ecosystem services sooner (stormwater runoff mitigation, cleaning soils and air, cooling air, habitat, etc).

Do not apply wood mulch every year if you have a natural garden employing matrix design — which you should be doing wink wink.

Don’t apply mulch deeply. Don’t put down 6″ and then move some to the side to get to soil to dig in something as that poor plant will be suffocated and drown (and still won’t be able to self sow and spread + less air AND water reaching the roots). Put less mulch on moist clay than you might on a drier sandy loam or loess. Put less mulch in shade than sun. Match plants to site, that way you don’t need to amend the soil no matter the fashion you do it in. Stop giving yourself more work. Stop giving yourself more work. Stop giving yourself more work. Stop giving your money away — or, at least use it to buy more plants and less wood mulch.

Folks will say “doesn’t wood mulch help retain soil moisture” and in my experience where we are that’s a big no. When it gets dry, say in mid to late summer, and then suddenly rains, it’s the wood mulch soaking up most of the moisture — and if you have several inches of mulch it takes longer for the rain to get down to the soil, then down into the soil where the roots are. Mulch is a barrier, and not a protective one. Kind of like weed cloth which is even worse stuff.

I watched a professional landscape crew today spread new mulch on beds around a strip mall. I guess they were tidying up. Helping suppress weeds. Blah blah blah. It was a lot of mulch around meatball shrubs and daylilies. DO NOT GARDEN LIKE THIS. It is not healthy. It is not sustainable. It is wasted money that should be going to more plants so you create a living green mulch that actually does far, far, far, more.

This is how I see wood mulch: pushed by an industry that needs continual revenue by making you think you have to work hard every spring. Mulch is an addiction, and in the end, makes you work harder by needing to add it over and over and never letting plants be plants.