Fairy Rings are Varieties of Common Mushrooms

Fairy Ring Type of Mushrooms

Brian Jervis: Ask A Master Gardener

Tuesday, August 19, 2017

Q: There are mushrooms all over my yard and that of my neighbor’s. Are they harmful? What should I do about them? Tom B., Jenks

A: The summer of 2017 has been a bit abnormal. We have had few century-degree days and much more rain than usual. While the rain is truly beneficial to our flower beds, gardens and lawns, it can cause other undesirable issues, such as mushrooms and fairy rings.

Mushrooms are actually part of a fungus that grows underground, well hidden from sight. Your yard is naturally full of fungi (plural for fungus) and spores, some harmless and some problematic. Fungi are interesting as they are one of the few things in our yard that do not get their nutrients from photosynthesis. Fungi receive nutrients by either decomposing or consuming organic matter.

Another phenomenon of mushrooms is commonly known as a fairy ring. These rings are also known as fairy circle, elf circle, elf ring or pixie ring and are produced by many varieties of underground fungi. Fairy rings are simply an organized pattern of fungi, typically circular in nature. They typically expand from a central point into an arc or circle and are particularly noticeable when they grow in our lawns.

The ring’s appearance is variable and may occur in all types of turf grass. They may appear as green rings, brown rings or simply a ring of mushrooms. The rings range from a few inches to many feet across and may persist for years.

The fungus that causes these rings feeds on organic matter in the soil. As it feeds, it frees up the nutrient nitrogen in the organics, accounting for the dark green rings. Typically, most lawn fungi and their mushrooms don’t actually harm the health of a lawn. However, in some cases, the older fungal mass may be dense enough to prevent water penetration and actually starve the grass from nutrients, thus producing a ring of dehydrated dead grass.

Mushrooms, toadstools or puffballs may appear overnight, especially after a rain. They are the fleshly, spore-bearing fruiting bodies of the underground fungi. To be on the safe side, all of these mushrooms and puffballs should be considered poisonous and should be removed as soon as possible.

Management is not easy. Once the disease appears, it is difficult to eliminate. There is no natural control. Most people opt for greening the lawn with recommended amounts of nitrogen fertilizer, which effectively masks/hides the ring but does not eliminate it. Other measures you can take: remove mushrooms by regular mowing or raking; water deeply to minimize the loss of grass due to the fungal dehydration; remove excess thatch and aerate compacted soils; encourage beneficial soil microbes by top dressing with a humus builder, such as well-aged manure or finished compost. However, if grass is lost, reseeding or re-sodding may be needed.

There are fungicides labeled for fairy ring control, but most are not effective and usually require a certified professional for application. Your mantra should be to fertilize, water, aerate and mow. Unfortunately, the only option for complete elimination of the fungus is to remove and replace the soil and grass.

Garden tips

·        Always follow directions on the labels of synthetic and natural pesticide products. Labels will always list where the product may be used and which pest it is certified to cover. If you spray pesticides, do it early in the morning or late in the evening after bees have returned to their colony.

·        If your tomatoes are too tall and gangly, now is a good time to prune the top of the plants by as much as ⅓ to ½, depending on the plant. This will stimulate new limb growth and new fruit production after it cools.

·        Reseeding fescue is best done from mid-September through mid-October. If you plan on reseeding, begin scouting for good seed, there is no “best” variety. Purchase a fescue blend of three or more varieties, with or without Kentucky bluegrass. Read the label on the seed bag. A good blend will have 0.01 percent or less of undesirable “other crop” seeds.