Decomposition Mushrooms

• The sight of several mushrooms suddenly popping up in a mulched landscape area can be worrisome, since fungi are associated with plant pathogens. But fruiting fungi that produce mushrooms are largely decomposers; they only consume dead matter to break it down into matter that plants can readily absorb. Mushroom fungi often feed on wood mulches in particular due to the high cellulose and carbon content. These fungi are beneficial, but should not be consumed. They need only be removed to keep small children or pets from accidentally consuming them.
  
  

Pathogen-Suppressant Mulch

• A study conducted on the ability of mulch to suppress fungi that harm plants found that pine bark mulch was able to do so around crops of medicinal ginger. In the paper "Composting; A Green Way to Save Money," professor Harry A.J. Hoitink of Ohio State University notes that coarse compost used as mulch has a similar ability to suppress fungi as those found in conventional compost. In these cases, mulch acts as an anti-fungal agent, meaning that some mulches can help safeguard plants against problematic fungi.
  
  

Problem Fungi

• Artillery fungus, slime molds and stink-horn fungus are types of nuisance fungi found in mulched areas. Artillery fungi spray sticky, staining black spores onto light surfaces (such as the sides of houses or vehicles) while stink-horn fungi just live up to their name, amassing a foul stench in the garden. Slime molds create an impervious layer that water often cannot penetrate. The roots under this fungal mat don't have access to rain or irrigation; this is a problem when the fungi spreads to wide areas.
  
  

Considerations

• Problem mushrooms or fungi fruiting bodies die when composted at hot temperatures. This is one fairly simple solution, although to date there is no known ecological remedy for artillery fungi. Mulch often instigates plant pathogen fungi problems when it is several inches thick or when it is packed against the crown of plants.