Slime mold not toxic despite its disgusting look

I found this odd-looking mass at the base of my tree in the village parkway. Is there something wrong with my tree?

— Emily Mathis, Highwood

There is nothing wrong with your tree that I can see from looking at the photo. The mass on the ground in the photo looks like dog vomit slime mold that is starting to dry up. Slime molds, of which there are many different kinds, can be found on a variety of surfaces, especially those with decomposing organic matter like there is around your tree. They first appear as slimy masses ranging from a few inches to over a foot across. They can be colorful with shades of orange, yellow, yellow green and even some blues and purples. Dog vomit slime mold is one of the most common and noticed slime molds and is typically seen on recently applied mulches such as shredded bark, wood chips and leaf mulch during periods of warm and rainy weather.

You may also see it during dry periods if you are watering on a regular basis. It can appear quickly and has a yellow, whitish, or tan color to it and look like a foamy patch of dog vomit or scrambled eggs. The initial more brightly colored mass will eventually turn to a more of a brown, leathery mass with crusty-looking fruiting bodies that are filled with spores. The spores are then dispersed to create new dog slime mold patches. This stage of its life cycle is much harder to notice in the garden. The dog vomit slime mold will not harm your plants, pets or family so there is no need to try to control it. There are no known chemical controls for getting rid of it anyway. The masses of slime molds will usually dry up and disappear in dry weather without any intervention on your part. You can speed up the process by removing unsightly patches in the landscape or simply using a cultivator to mix it in with the ground.

For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.