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Harmless Slime Mold on Mulch: Fungus That Disappears in Dry Weather

What It Is

The yellow, vomit‑like blob that turns splotchy, hardens, and releases brown dust when wet is a slime mold (a fungus). It feeds on decaying organic matter in thick mulch.

No Harm to Plants

Slime mold is harmless to flowers and shrubs. It disappears when weather dries. Copper fungicide can accelerate its demise, but treatment is unnecessary.

Pests: Yellow "Vomit Fungus" in Flower Beds: Slime Mold; Slime Mold on Lawn: Harmless, Short-Lived; Pink Foam in Flower Beds: Harmless Vomit Fungus; White Powder on Soil: Beneficial Fungus or Root Rot? Get a Professional Diagnosis Before Spraying; Long-Lasting Mulch Alternatives for Large Flower Beds; Fungus in Indoor Mulch: Remove It Immediately; Designing a Sunny Perennial Border in Seattle: 30+ Plant Ideas for a 30x4 ft Raised Bed; Lawn Fungus Spread to Shrubs: Yes, But Limited; Yellow Fungus on Mulch: Why It's a Good Sign and How to Manage Appearance; Identifying and Managing Stinkhorn Fungi in Flower Beds

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