Dog Vomit Slime Mold: A Photo Journal

(Updated: June 12, 2024, 12:49 p.m.)
Bright yellow slime mold decomposing hardwood mulch
Dog Vomit Slime Mold is most noticeable during this first bright yellow stage. But do not worry when you see it.

When you see a mustard yellow slimy blob on your raised beds, relax and enjoy the show.

Yesterday's bright yellow had spread and muted to a puffy tan color resembling a funnel cake.
One day later the bright yellow had spread and muted to a puffy tan color resembling a funnel cake.

The mold shrank into a more crusty, gray flecked cookie by day 3.
By the third day, the mold shrank into a more crusty, gray flecked cookie.

crumbling dry beige blob
The fourth day was even more disintegrated and any disturbance sent clouds of spores wafting.

The latin name is Fuligo septica but it is commonly referred to as ‘Dog Vomit Slime Mold”. Ewwww. Slime molds are most often found on fresh organic material in warm and humid conditions. It has been thriving on my newly spread hardwood mulch the past few days of mid June.

It has come to decompose the hardwood mulch and will not affect any living plants. If you really hate the look and cannot wait a few days for it to pass, take a garden fork and toss the mass under shrubs or onto your compost pile.

When the blob enters its final stage, it is dry and crumbly. Any slight disturbance, even watering with the garden hose, will cause a plume of spores to erupt. These spores remain viable and will wait for the perfect conditions to germinate to start the process again.

Older more seasoned mulch is less likely to support this mold so you may never notice it unless you’ve recently spread fresh hardwood mulch on your garden beds. The breaking-down of mulch is a wonderful necessary process that creates ideal conditions for everything you are trying to grow. Cheers to Dog Vomit!