Mushrooms Growing in the Lawn and Mulch
Posted: July 9, 2015
Messages and emails have been coming into Extension offices the past few weeks about slug activity in landscapes and vegetable fields as a result of this non-stop rain. As of this week, the rainy weather hasn’t really stopped and the slimy critters are still running amok. Other organisms are also thriving in this climate; mushrooms.
Comments and calls have been coming into the office about mushrooms growing in the lawn and mulch and homeowners want to know what action can be taken, some almost in panic mode. Understanding the role of mushrooms in the environment can often ease the fear.
The mushrooms we commonly see in our landscape are fungi. Instead of the thread like structures often associated with fungi, we are seeing the fruiting bodies. Mushrooms come in all shades of color, except green. In plants, green signifies the presence of chlorophyll, necessary for photosynthesis which allows the plant to produce its own food and energy. Since mushrooms don’t have chlorophyll to capture the sun and produce food, they have to obtain energy in a different manner.
The little brown dots to the right of the marigold are the bird’s nest fungi growing in the mulch. Photo: Tom Butzler
Everything in the landscape rots over time (okay, except for hardscape items like brick walkways). Mushrooms aid in this destructive process and utilize decaying items to obtain their energy. Nutrients are also released in this activity and become available to nearby plant roots.
Close-up of the bird’s nest fungi. They resemble tiny, gray to brown bird’s nests or splash cups with eggs. Photo: Tom Butzler
While there are some fungi that will attack living plants to obtain energy (parasites, and these are ones to worry about), the mushrooms we see in the landscape are causing no harm to surrounding plants. That being said, many homeowners see mushrooms in the yard or mulch as an aesthetic nuisance (although some might be harmful if eaten).
For mushrooms growing in the lawn, simply mow over them. These will eventually disappear when drier weather remains in place or when the organic matter it is feeding on is completely decomposed. Fungi in the mulch can be eliminated by simply raking over the mulch.
Penn State has a consumer oriented color brochure of fungi most likely found in your clients' yards entitled What Is Growing in My Landscape Mulch? that gives more detailed description on identification and other additional information.