Switched to a 4-inch mulch ring on a stressed red maple and the soil got weird

I had a client's red maple in Springfield showing drought stress, so I expanded their mulch ring from 2 feet to 4 feet with a shredded hardwood blend. Two weeks later, the soil underneath felt cold and slimy, and I'm worried I created a moisture barrier that's too thick. Has anyone else seen this happen when you increase mulch volume too quickly?

3 comments

3 Comments

jamie94019d ago

That slimy feeling is a classic sign of anaerobic soil, basically it's suffocating. A 4-inch layer is the max you want, but going from a 2-foot ring to a 4-foot ring all at once can shock the soil's moisture balance, especially with fresh hardwood. I'd pull the mulch back from the trunk a good 6 inches and fluff up the existing layer to let it breathe. Sometimes you gotta temporarily reduce the thickness to let things dry out a bit.

kimr7418d ago

Yeah, I read something similar about that slimy layer, and @jamie940 is totally right about it meaning no air. I had the same thing happen when I piled mulch too high around a maple last spring. Fluffing it up and keeping it away from the bark made a huge difference after a couple weeks.

thomas_torres18d ago

I saw that slimy black layer on my own mulch last year after heavy rains. The problem is that compacted layer blocks all the air from reaching the tree roots. I had to use a garden fork to really turn over the whole mulch bed, not just fluff the top. It took about a month for the soil to dry out and the smell to go away. Now I never go over 3 inches deep, even with older mulch.