Mulches are commonly used in landscapes to limit the growth of weeds, provide a
“blanket” effect moderating soil temperatures year round, and conserving moisture. The
application of mulch in a landscape project also gives that finished look completing
flower beds and gardens.
Common mulches are a mixture of shredded wood and bark fines. As with other organic
matter, wood and bark will decompose over time. Bacteria and Fungi are the primary
organisms involved. Through carbon-based compounds found in bark and wood, the
bacteria and fungi draw the energy they need to grow. Bacteria in mulch is microscopic
and therefore not visible. Fungi can also be microscopic, but many times will develop
structures visible to the eye.
The two most common types fungi presented here in Central Virginia are Mushrooms
and Slime Molds. Mushrooms are produced by many different species of fungi. They
also are commonly referred to as toadstools. They emerge in many colors, shapes and
sizes. Some appear and disappear the same day. Others appear and remain in the mulch
for days, weeks, or months. You can remove them if you do not like their appearance;
however they are of no harm to your landscape. They may be poisonous if eaten. Slime
Mold is a fungus which presents itself in an unpleasant fashion. “Dog Vomit” mold is
it’s other common name. It starts as a bright yellow or orange appearance. It’s slimy
mass can spread up to a foot across. Eventually these molds dry and take on a dry white
powdery appearance. Most people prefer to remove the fungus to a compost pile,
household garbage or a spot in the yard away from the mulch. If left in place it will dry
and eventually disappear. Slime Mold is not of any danger to you or your landscape.
Both fungi mainly appear from April thru October. Most appear following rainy weather.
Feel free to contact us if you have any questions about the above mentioned fungi or any
other species found growing in your yard or mulch.