This has been the year for mushrooms. Homeowners have had them popping up all over yards and gardens and have been flooding garden centers and the Master Gardener Plant Clinic with questions about what they are and how to deal with them.
To “deal with” mushrooms, we need to understand just what they are. The mushrooms we see above ground are really the fruiting body of a larger mass of fungi underground. The fungi we can’t see are one of nature’s most prolific and efficient soil builders. They are the beginning of the decomposition cycle that eventually breaks down all the raw organic material that accumulates around us.
Fungi are made up of very fine threads or mycelia that colonize raw organic material such as wood, leaves and grass clippings that come into contact with the soil. They penetrate material and break it down, using enzymes, into compounds that are further broken down by other microbes, worms and soil insects, releasing nutrients to plants and animals up through the food chain. Without the work of the mycelia, we would be buried in debris, and life as we know it would be very different. At certain times of the year when temperatures and humidity are just right, the fungi send up mushrooms to spread spores and thereby reproduce. Conditions for this have been particularly good this fall.
As important as fungi’s role is in decomposition, mushrooms evoke a lot of negative reactions in people. Historically, they were the source of many folklore myths and legends down through the ages. Mushrooms were thought to be signs of fairies, evil spirits or witchcraft and those that worked with them were both feared and respected in their communities. Beyond history, eating the wrong mushrooms can cause a number of medical problems, including death, and so people tend to stay away from them.
The presence of mushrooms in a lawn or garden means that fungi have found a fresh source of organic material in the area. It could be wood left over from a project and buried underground or an overabundance of grass clippings or other garden debris. Trees that are suffering from root rot often have mushrooms growing around the base of the tree because the roots are dying and being colonized by fungi. Bark brought in for mulch can already have fungi in it when it is delivered to you.
Because fungi are always present in the lawn and garden environment, controlling the mushrooms that sprout from them is difficult. Fungicides are available, but because mushrooms often randomly emerge, it’s like fighting a house fire with a very expensive garden hose. To really control them means altering the environment and removing the wood or organic material the mycelia are breaking down. Maintaining proper drainage and lawn care will help reduce their presence in lawns. Aerating fairy ring circles with a pitchfork and then watering them with water mixed with a little bit of dish soap for several weeks helps disrupt their growth enough to reduce their presence.