Over the years I’ve promoted the use of organic mulches (see tomorrow’s entry). Occasionally, unexpected “issues” arise, such as the phallus-shaped dog stinkhorn fungus (Mutinus canines) or the neon yellow, foamy-looking slime mold that looks like a colorized version of the blob. These invaders may be unsightly, but they are harmless.
The neon yellow slimes molds are called scrambled-egg slime or the “dog vomit fungus.” They appear from spring through fall, usually when moisture is available.
Slime molds spread by spores, which could have already been present on the mulch or were blown in by the wind. When the spores come into contact with water, they burst and release amoeba-like cells. These cells eventually unite with other cells to produce a plasmodium, that scary, frothy-looking mass. It flows over mulch, sidewalks, and driveways in search of fungi, bacteria, and decaying organic matter. Scientists have discovered that the plasmodium moves as much as 2 feet or more per day in response to light and food. Eventually, the slime mold reaches the reproductive phase when it dries and develops mushroom-like fruiting bodies that release the dustlike spores.
Because this curiosity eventually dries up and disappears, no control is necessary. However, if its appearance bothers you, break it apart with a garden rake with water from the hose. Slime mold invasions can be avoided by adjusting the irrigation system to prevent the mulch from becoming too wet. Also, periodically fluffing up the mulch with a rake will help aerate it and speed up drying.
© Bob Polomski