A: Patience. There are all sorts of fungi in any healthy soil, most of which are harmless. Mostly, they decay dead vegetation, which is why you see fungal strands all over your mulch right now. The fungi primarily live in the soil, and what you’re seeing is simply their version of blooming, to spread themselves on the wind. Fungi, toadstools, and slime molds (nasty looking things that look like a pet vomited), it’s all the same thing. They’re tiny living things that feed on the compost in the soil and the wood of your mulch, breaking them down…an important part of the cycle of plant nutrition.
If these clumps are unsightly, just pick them up with a flat shovel and throw them away. Otherwise, don’t worry about it. Most of these odd little growths on the surface will burn up in the heat, and largely go away without you having to do much at all. Your plants nearby are in no danger, and unless your allergies are acting up, neither are you.
Burton specializes in diagnosing and solving plant problems. If you have a question for Burton, please email him at firstname.lastname@example.org and include photos showing the problem.