Your harmless 'slime mold' (not a mold or a fungus) can be avoided if you stop using organic mulches completely. Since that is not a good option for your soil or plants, I suggest that you simply scrape them away if they offend you.

Lime would not be the solution....1) it wouldn't prevent the organism from growing and 2) it could change the pH of your soil.

Mushrooms coming out of the ground, by the way, are a sign that important decomposition is happening under the soil surface, AND that an exceedingly beneficial relationship may be taking place between the fungus organism and the roots of your trees (and other plants). Mushrooms are a good thing.

You could buy treated mulch so that this does not happen, or plastic mulch, maybe even shredded rubber. The reason this is happening is because you live in an area with a high level of spores for this fungus or bacteria , Maybe you could try different types of orgainic mulch to see if it hinders this from happening, different trees have different compounds to fight off different decomposers, but personally I would recomend just leaving it, it helps provide your plants with nutrients.

Ummm, brendan...slime mold is neither a fungus NOR a bacteria. The organism is ubiquitous in all but the most sterile of environments....which would not be healthy for human nor beast....nor plant, lol.

There is no reason to do anything but rake the area to disturb it. Prevention should not even be a consideration. Plastic mulch? Yikes.

Slime molds are really fascinating. I've seen two this spring, one yellow, and one pink. They have several stages they go through and each one is really interesting. Why not watch them and learn?

Lainey