Unsightly slime mold sighting on landscape mulch

Wet weather brings out “dog vomit” slime mold in landscape mulch.

“Dog vomit” slime mold commonly occurs on landscape mulch after heavy spring rains. Photo credit: Jill O’Donnell, MSU Extension
“Dog vomit” slime mold commonly occurs on landscape mulch after heavy spring rains. Photo credit: Jill O’Donnell, MSU Extension

Spring is normally a time of beauty for gardeners in Michigan. However, our recent wet weather can lead to growth of a decidedly unattractive slime mold on landscape mulch. The scientific name of the mold is Fuligo septicai, but it is more commonly referred to as “dog vomit slime mold” or “dog vomit fungus.”

The mold will initially appear as a bight yellow mass, sometimes called the “scrambled egg fungus,” which is the beginning of its fruiting state. The mold then turns into a tan or brown mass that leads to its other common name.

From a landscape health perspective, Michigan State University Extension assures dog vomit slime mold is strictly an aesthetic issue. The slime mold is saprophytic (feeds on dead material) and does not harm plants. The spores are widespread and it usually appears in mulch in spring or early summer after soaking rains. Homeowners or landscapers may want to scoop up the offending masses in order to tidy up beds, but otherwise no control is warranted.

Dr. Cregg's work is funded in part by MSU's AgBioResearch.

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