Fairy rings appear as large round patches of discoloured turf, with the perimeter of the patch usually being bright green with a ring of mushrooms around it.
What is Fairy Ring?
A ring of fairies dancing… well not quite, but folklores of the British Isles about fairies are the reason why Fairy Ring has its name. Fairy Rings are in fact fungal formations that can form in your lawn. This fungal disease is particularly important to be aware of if you have mushrooms appearing in your lawn. Fairy rings appear as large round patches of discoloured turf, with the perimeter of the patch usually being bright green with a ring of mushrooms around it.
Why do Fairy Rings occur?
A Fairy Ring will form from mycelium (the vegetative part of a fungus) which has branching white long fibres called hyphae. These hyphae create a circular mat of growth and when two mycelium join they are able to create the fruiting body that produces a mushroom. Fairy Rings usually consist of field mushrooms that form into circles approximately 2 metres in diameter. Soils that are high in organic matter are more susceptible to Fairy Ring. If you have a high amount of thatch it is also possible they may appear.
Mushrooms themselves don’t cause any really harm to your grass, but Fairy Ring does. The mat that forms beneath the surface makes water penetrations to the grass roots difficult and depletes nutrients in the soil. It can sometimes also release a toxin that will kill off the turf within the ring.
Once Fairy Rings occurs it is extremely difficult to eradicate, and most fungicides are not effective.
As there are no specific treatments readily available, the method of treating Fairy Rings is much the same as mushrooms, which you can read more about here.
A well-maintained lawn will rarely see Fairy Ring appear, so regular fertilising, mowing, thatch reduction and aerating will usually ensure it doesn’t occur. When installing a new lawn, make sure you remove dead or dying organic matter like tree roots that may provide a source of food for fungus to grow from.