The recent wet weather has led to an increase in the appearance of mushrooms. The Cooperative Extension office has received many calls about the new crops of mushrooms and how to eliminate them from the landscape. Mushrooms are the above-ground fruiting bodies of fungi that live in the soil. Sid Mullis, County Extension Agent for Richmond County, explained it best by stating, “Mushrooms are the flower of the fungus.” Mushrooms usually emerge when rain follows extended dry periods. Dry weather stresses the fungi. When water becomes available, it triggers the reproductive mechanism, and we get mushrooms.
These fungi feed on decaying organic matter, such as old roots, stumps, and thatch. When these fungi are present in your soils or mulched areas, mushrooms of various shapes and sizes will seem to pop up overnight after a rain event. While they may be unsightly, many of these fungi are completely harmless to the landscape. Mushrooms may be removed by hand-picking, but this does not remove the underlying fungus in the soil. The mushrooms may return when conditions are favorable.
One of the larger mushrooms and one that always seems to cross my desk is a type of Bolete. These specimens are up to eight inch across, white in color, with pores on the underside of the cap. The pores are a unique identifier for this type of mushroom. Boletes form an intimate relationship with the roots of trees and other plants. This relationship is called a mycorrhizal association. It is a symbiotic relationship between the fungus and the plant’s roots that extend the plants reach to water and nutrients. As the fungus invades the roots of a tree or other plant roots, absorptive property of the fungus extracts minerals from the soil and brings them into the host plant. In return, the fungus obtains vitamins and other organic materials from the tree.
One of the most eye-catching and descriptively-named fungi is a type of slime mold commonly referred to as “dog vomit”. Fuligo septica, the scientific name for this type of slime mold, typically occurs on mulch. It begins only a few inches across, but rapidly grows up to several feet in diameter. Colors vary from bright yellow or orange and fades to brown or tan as it dries. Slime molds do not harm plants and dry up within a few days of forming. If their appearance is offensive, they can be scooped up and thrown away.
Another interesting fungus family is the Phallaceae which includes the mushroom known as stinkhorns. Stinkhorns are a group of mushrooms most people often smell before they see. While the smell or appearance of this mushroom may be undesirable, they are beneficial to the landscape. This fungus is a decomposer, and it is considered beneficial because it helps break down decaying plant material. Stinkhorns do not harm landscape plants or grasses. If the smell is unbearable, remove the mushroom and place it into a sealable plastic container.
It is a misconception that mushrooms are a sign of soil problems. Many fungi are a vital part of a healthy soil that decomposes dead plants and other organic matter. There are some fungi that can cause harm to the landscape. The type of fungi would need to be identified to determine if it would be detrimental to the lawn. Because mushrooms are the fruiting bodies of fungi, removing them doesn’t kill the underground fungi from which they are growing.
The main reasons for removing mushrooms from lawns are to remove the risk for children and pets and to improve a lawn’s appearance. It is never advised to eat an unidentified mushroom from the landscape. Some mushrooms are poisonous to humans and animals. To remove mushrooms in the landscape, pull them up or run them over with the lawn mower. The mushrooms, however, may reappear when conditions are favorable.