Breeze,

I don't have any experience with rubber mulch rings.

I recently read this article that mentioned them.

Here is a link that might be useful: The myth of rubberized landscapes

I work for a school District that uses rubberized mulch in the play ground. Somehow a fire started, and traveled underneath the mulch. Kind of scary as it was not so well noticed. The guys that cleaned it up were covered with black soot from head to toe! What does it do for the soil? Does it add nutrients to the soil? For what its worth, Mary

I use the rubber tree rings on my maples and dogwoods. I like the neat clean look they provide. They hold the moisture in also. They are quite different from loose rubber mulch. I wouldn't use that mulch at all, for a variety of reasons. Don't understand why the OP stopped using the rings because of sow bugs underneath. They don't hurt anything and indicate a moist, cool environment, which is what you want.

rubber mulch absolutely does anything benefical to the ground other than keeping weeds out. Organic mulch is much better way to go as it improves the soil, improve growth, improve health, better moisture retention, etc.

It is a myth that sow bugs/pill bugs/rolly pollies are harmless. They are just as bad as squirrels but worse since they can hide in pots. I mainly grow orchids and there is nothing those yard-shrimp like more than to munch on fresh growing root tips. I've seen them in the act. I've also seen them eating my clematis. For those reasons I'm paranoid about them eating my maples.

I have no shortage of natural mulch but I also have the rubber rings. The wind often blows the mulch (leaves) away from around my trees. I would use them during winter and summer if at all, our dryest times of year. I'm a little bit worried about summer however because the rings are black. It gets hot enough as it is and I wonder about having a black mat absorbing heat when it is already over 100 F. Luckily we've had mild and wet summers the past two years so there has not been a great need for mulch.

Personally, I wouldn't use the things at all, but most particularly, I'd keep them away from maples. One of the primary complaints against rubber mulches is that they leach heavy metals and in particular, zinc. Both maples and oaks are quite sensitive to zinc toxicity. Zinc is also more easily accessed by plant roots in acidic soils, which J. maples prefer, compounding the problem. I just wouldn't want to risk the health of my trees for the sake of the ease of care a rubber mulch or mulch mat might provide.

>They don't hurt anythingIn addition to what gardengal48 posted, read article at link posted above.

Circular rubber mulch mats?!! You gotta be kidding. I don't want my yard looking like a cartoon.