Mushrooms in Landscapes

Mushrooms tend to pop up during moist conditions, alarming homeowners.

The questions we receive are:

• Are they harmful to my children or pets?
• Are they associated with a soil disease?
• How do I get rid of them?

In most cases, the mushrooms are completely harmless. They are part of natural decomposition and can help benefit surrounding plants by releasing nutrients that have been unavailable in the soil.

There are two types of beneficial mushrooms:

Symbiotic – (Greater than 2 inches in diameter) a mutually beneficial relationship with other living plants. These help with the uptake of nutrients and water more efficiently, like mycorrhizae.

Saprophytic – (Less than 2 inches in diameter) living on dead organic matter. These release nutrients from decomposing material and can benefit surrounding plants by making them available.

There are several mushrooms from harmful fungi. Armillaria mellea is a root rot that has honey colored mushrooms (pictured below). This fungus is a naturally occurring in the Northwest. It is becoming more common in urban landscapes due to poor construction practices.

Another offender is fairy ring. This is common in lawns (pictured below). The mushrooms are visible in spring and summer. The only control method is removal of mushrooms when they appear to prevent the fungus from spreading. We recommend watering deeply and infrequently, along with moderate fertilizer application. Typically, fairy ring is not detrimental to lawn health.

To find out more

If you have a serious interest in mushrooms and fungus, a good field guide for the amateur mycologist is Mushrooms Demystified by David Arora. A good Northwest field guide is The New Savory Wild Mushroom by Margaret McKenny, Joseph F. Ammirati & Daniel E. Stuntz.
For photos of many different mushrooms, visit the Snohomish Mycological Society, www.scmsfungi. org/fotos.htm.

Reference

Mushrooms in Yards, http://gardening.wsu.edu/library/lpro006/ lpro006.htm.