Mushrooms Are Growing in Landscaping

Beneficial Mushrooms

• Most mushrooms are signs of beneficial fungi. Fungi feed on organic matter, decomposing it. Once the matter is sufficiently broken down, it provides nutrients for the soil and surrounding plants. Some beneficial fungi have established symbiotic relationships with certain plants. One example of this is mycorrhizae, which attaches to trees, shrubs and other herbaceous roots. It helps these plants absorb nutrients and water from the soil and may or may not produce mushrooms in the nearby grass. Many types of evergreens, including pine trees, grow poorly or not at all without mycorrhizae's assistance.

Fairy Rings

• Fairy ring fungus, which can be produced by several fungal species including Marasmius oreades and the Lepiota species, is one of the only types of fungi all grasses are susceptible to and that might cause damage. Mushrooms sometimes accompany these rings. Fairy ring fungus first appears as circular or semi-circular areas of tall grass in diameters of 1 to 12 feet, but the fungal colony can expand for years and eventually take over a lawn or landscaped area. While a mild case of fairy ring fungus only stimulates grass growth, a heavier infestation can prevent or kill grass in the same circular or semi-circular patterns.

Poisonous Mushrooms

• While most mushrooms are harmless, there are fatally poisonous species. These killers are difficult to identify and there are no simple tests to confirm their poisonous nature. The University of California recommends never ingesting any wild mushroom for this reason unless you are an expert and to remove mushrooms from landscaping and lawns visited by children and pets. The mushroom responsible for 90 percent of fatal poisonings is Amanita phalloides, which looks and tastes a lot like edible mushrooms; it is small, with a light-colored cap and stem, and has a mild, pleasant taste. Mushroom poisonings often go undetected until it is too late because symptoms can take as long as 36 hours to appear and then present much as a severe intestinal flu.

How to Reduce Mushroom Populations

• You will probably never be able to completely eliminate mushrooms from landscaping, but reducing the population is possible. Mushrooms are just an outward sign of the less visible fungus that is probably fully integrated into the surrounding soil. To reduce mushroom populations, pick what mushrooms you see and then remove the factors that make it easy for them to grow -- mainly excess moisture and rotting organic material, like wood debris or food scraps. The primary reasons homeowners choose to remove mushrooms is for appearances and to protect children and pets from possibly poisonous species.