The appearance of colored slime and smelly protrusions in your mulch may be reminiscent of a science fiction movie, but it’s a natural occurrence during wet weather periods. Heavy rain brings fungus growth in decaying wood and mulched areas. The fungus takes on a variety of appearances, including various colored slimy masses called Slime Mold or fingerlike protrusions poking through the mulch called Stinkhorns. Stinkhorns are also a variety of colors and may pronounce their appearance with a strong odor.
While their appearance may be disturbing, the fungus growth is not considered dangerous or damaging in the landscape unless it grows so large it smothers plant material. It is not recommended to break apart the fungus in the mulch. Splitting and tearing apart the fungus will spread spores throughout the area, creating more fungal growth. Allow the fungus to dry and then carefully remove in one piece for disposal. Once drier weather appears, the fungus will disappear.