Artillery fungus (Sphaerobulus stellatus) is a fungus that develops on rotting wood in a moist environment. What makes it unique is the way it shoots its spores into the air after so much liquid has built up in its mature fruiting bodies that they burst open.
Artillery fungus is a wood-decaying fungus that likes to live in landscape mulch. In its natural habitat, artillery fungi shoot spores towards sunlight. At your home, the fungus may behave differently. Lack of direct sunlight will cause the fungi to shoot spores at reflective surfaces, like white siding or cars. Obviously the dark spores are easily spotted on lighter color surfaces as well.
Artillery fungus has been more prevalent than it has in the past. Landscaping over the past several decades has included the use of wood mulch. In the past, purely bark mulch would have been more typical. Cool spring and fall periods will always yield more of the fungus as well. It’s common to notice this fungi growing in shady environments and on the east and north sides of homes. Beds that aren’t in full sun most of the day are most susceptible. However, artillery fungus has been found in full-sun environments as well.
Spores are very sticky and don’t take long to fasten themselves to surfaces. This makes them almost impossible to remove with most cleaners. They don’t pose any damage risk to surfaces other than cosmetic.