What Are Fairy Rings, and What Do They Mean For Your Garden?

Have you ever walked outside one day shortly after a rain and seen a large, circular ring of mushrooms growing in your lawn or garden? Fairy rings evoke images of magic and mystery but what exactly are they? In this article, gardening (and mushroom) enthusiast Liessa Bowen dives into the realm of the fairy rings to demystify these other-worldly occurrences.

Mushrooms forming a circle, growing in the backyard, under some shade created by trees.

Contents

Fairy rings may seem like a mysterious phenomenon, or they may just be a nuisance to your garden, depending on your individual perspective. These circular rings of mushrooms are a common sight in grassy lawns and moist woodlands. If you’ve ever seen a circle of mushrooms, you’ve probably wondered what it is, how it got there, and what it means.

Fairy rings come from a fungus that grows underground during most of the year. It emerges as a ring of capped mushrooms at a certain time each year. Chances are, if you have seen one in your yard during the previous year, you’ll probably see one again this year. You will likely see it next year as well because these mushrooms can be remarkably long-lived

Once you start to understand how mushrooms grow, the mystery starts to make sense. Mushrooms are fascinating organisms. As you learn more about them, you may be drawn into their mysterious beauty. Perhaps you will better appreciate the mushrooms growing in your yard. If not, you will at least be better informed about what it is, and how to deal with it. 

Let’s dive right into the enchanting world of this fungus. We will explore exactly what these mysterious mushroom circles are and what they mean for your lawn and garden.

The Short Answer

Mushrooms growing among green grass, forming a circle.
Dozens of different species of mushrooms are capable of forming them.

A fairy ring is a fungal growth that appears in your lawn or garden. Dozens of different species of mushrooms are capable of forming these circles. Since there are so many species that form circles, you won’t automatically know what fungal species it belongs to.

These growths are caused by the outward spread of the fungal “mycelium,” which is an intricate system of underground, root-like growth. As the mycelium spreads, it occasionally sends up fruiting bodies—the capped mushrooms we see above ground.

The Long Answer

Here are more details about these intriguing growths, and what to do about them.

Fairy Folk

A big mushroom arc created by wild mushrooms growing in a forest, in between plants.
They were believed to be dangerous, perhaps a portal to another world.

Throughout history, fairy rings have touched the imagination. They appear in folk tales, folk songs, art, poetry, and ancient superstitions. There are stories about mystical circles created by dragons, elves, witches, and, of course, fairies. They were believed to be dangerous, perhaps a portal to another world. Some people believed that those who wandered into one would be transported into the realm of mystical folk. Other tales describe underground fairy villages outlined by the fungi.

We have enough scientific understanding today to know that these are actually the result of a natural earthly process and no folklore or elves were involved. Simply put, every circle you see is caused by a single fungus that grows and spreads underground until it reaches fruiting maturity. When you have the right combination of fungal maturity and favorable environmental conditions, the mushrooms emerge and we see a halo of growth.

Species

A poisonous type of orange mushrooms, all growing to form a circle.
Some species are edible, while others are extremely poisonous.

It is estimated that about 60 different species are capable of forming halos. The species vary by season and location although most develop in the summer and fall throughout North America and Europe. 

There is a species of mushroom known as the “Fairy Ring Mushroom” (Marasmius oreades), but this is by no means the only species responsible for this phenomenon. Other familiar ring-forming mushrooms include the “field fungus,” “meadow mushroom,” “fly agaric,” “fairy ring champignon,” and the “giant funnel,” to name just a few. 

Most fruiting bodies have stalks and gilled caps that open into parasol-like fruiting bodies. Some species are edible, while others are extremely poisonous. It’s critically important never to eat a mushroom foraged in the wild unless you are 100% sure what you’re eating. There are many mushroom lookalikes that can be easily confused and cause unintended illness and even death.  

Growth

Wild mushrooms following the shape of a circle, growing in a lawn.
Over time, the mat of mycelium grows larger and larger.

All mushrooms start with a single spore. If a spore lands in a favorable location, it germinates, much like a seed. But unlike a seed, a spore doesn’t develop roots. Instead, it first forms a few tiny white threads known as hyphae. If the environment continues to be favorable for growth, these hyphae quickly form a mat of intertwining underground threads known collectively as mycelium.

Over time, the mat of mycelium grows larger and larger. In the case of a fairy ring species, the mat of mycelium expands outwards in a roughly circular shape. However, it isn’t always a complete circle. Sometimes, the circle is interrupted by poor conditions, such as disturbed soil or chemical interference, and you’ll see a semi-circle instead. This is still a fairy ring; it just didn’t fully develop.

The inner parts of the mycelium circle die as the outer parts continue to expand, keeping its halo shape. Warm weather and good rainfall are all it takes to trigger the fruiting bodies to form. The familiar mushrooms that you see above ground are called fruiting bodies because they contain spores

One day, you look out your window, and there’s a ring of mushrooms! It does seem a bit like magic. As soon as they mature, they release thousands of spores. Some of these spores fall to the ground, while others get blown away. Most will never germinate, but if one of these spores lands in a favorable location, the next generation has a chance to grow.

Age

Brown mushrooms creating an arc while growing from the ground, with a ground of grey mushrooms growing in the center of the circle.
They develop an ever-expanding mass of mycelium.

It takes about a year for a ring to form. For most of the first year, however, you probably won’t know that it is developing. The mass of mycelium is growing underground, just below the soil surface. During this time, the mycelium mat grows rapidly, and you don’t even notice. The summer following the initial spore development, when environmental conditions are just right, usually warm and moist, the circle of mushrooms pops up out of the ground!

These fungi develop an ever-expanding mass of mycelium. In fact, they can keep growing, year after year, for hundreds of years. The oldest known fairy ring is located in France and is believed to be over 700 years old! As long as the mycelium is alive and well with enough nutrients and enough moisture, the fruiting mushrooms will emerge each year in larger and larger circles.

Fairy Rings in Your Garden

White mushrooms with flat heads, forming an arc, growing in the garden.
When one starts to develop, you may notice that a circular plot of grass looks extra thick and green.

Now that we know all about how these fungi grow, does this giant mycelial system have an impact on your lawn and garden? Fungi feed on dead and decaying matter such as rotten wood, dead roots, and organic matter in the top layer of soil. Since they take a while to develop from a mycelial mat to a ring of fungi a fairy ring will typically develop beneath your lawn or in a relatively undisturbed woodland area rather than in your actively cultivated garden.

When a new fungus starts to develop, you may notice that a circular plot of grass looks extra thick and green. This is because the mycelium is adding nutrients to the soil in preparation for its own growth, which in turn benefits your lawn, but only temporarily. As the mycelium continues to grow outwards, it then uses up the nutrients it just deposited, essentially removing those nutrients from the soil again. That lush patch of grass then turns yellow and dies.

What to Do?

Closeup of wild mushrooms having triangular heads that almost look like umbrellas, growing on a lawn with green grass.
You can collect the fruiting bodies when they emerge, bag them, and throw them in the trash.

The first thing to remember when you see a ring crop up in your yard is: It is not caused by fairies, elves, or other mythical creatures. It’s reasonable, however, to wonder what you should do about it. You have several options, depending on your personal preferences.

Do Nothing

If you do nothing, the mushrooms will grow, die back, and probably come back at the same time each year for several years. Many species will cause patches of your lawn to become extra lush and green, followed by yellowing and dying, as the mushrooms release extra nutrients and then absorb them again. So a lawn with an active fairy ring will be a little challenging to maintain and keep uniformly green.

Throw Them Out

You can collect the mushrooms when they emerge, bag them, and throw them in the trash. Or if your community collects yard waste, you can put them in your community yard waste bin. Organic matter collected in community composting programs is generally used to create large amounts of mulch and compost.

Compost the Mushrooms

If you have a compost pile, you can compost lawn mushrooms, but keep in mind that all mushrooms grow from spores. By the time you have picked a mushroom, it is already producing spores. If these spores survive your composting process, they might spread and start a new colony when you use your compost. Another thing to remember is that, just because you picked the mushrooms, the mycelium is still alive and well underground, and you’ll still get more mushrooms next year.

Remove the Mycelium

If you’re really determined, you could, in theory, remove a fairy ring fungus from your yard. Since the fungal colony extends far and wide, much more than you see above ground, you would need to dig up and remove all the turf within the fairy ring, extending approximately 12 to 18 inches beyond the edges of the fairy ring to catch the newest mycelium growth. And after all this work, you may not even have removed all the mycelium.

You can either remove the sod entirely or repeatedly cultivate the entire area with a tiller to thoroughly disturb the mycelium mat. Then replace with fresh, disease-free sod or reseed the area. This process doesn’t guarantee that you will remove the entire fairy ring but it can be very effective.

Thoroughly Soak the Area

A fairy ring mushroom colony can be killed by persistent soaking. You will need to use a lot of water for this method to be effective. Use a sprinkler or soaker hose to thoroughly soak the area every day for about a month. Try aerating the soil before you do this to help the soil absorb moisture. After a regular regimen of thorough soaking, many fairy ring fungi will simply rot because they need some air flow to survive.

Mask the Effects

One option that some people prefer is to simply mask the effects of a fairy ring. While I don’t personally recommend this method because it involves applying extra fertilizers to your lawn, you should still know how this affects fairy rings.

Applying lawn fertilizers will help your lawn stay lush and green, even as the fungus in the soil is depleting soil nutrients. Adding lawn fertilizers won’t make the fairy ring go away, and you will still have outcroppings of mushrooms, but at least you won’t have dead, bare patches of grass.

Don’t Eat Them

Don’t collect and eat the mushrooms. Many species of mushrooms that form fairy rings are poisonous and can cause illnesses, ranging from mild to severe. Keep children and pets away from fairy ring mushrooms as well, and make sure they can’t ingest any wild mushrooms that have any chance of causing harm.

Maintain a Healthy Lawn

The most important thing is to keep your lawn and garden healthy. A healthy lawn and garden are beautiful, resilient, and resist disease. A fairy ring is often a sign of an unhealthy lawn.

    • Aerate your lawn regularly.

    • Keep your lawn sufficiently watered.

    • Feed your soil with natural organic matter rather than chemical fertilizers.

    • Mow your lawn using a high setting for healthier grass.

    • Remove weeds by hand rather than applying pesticides.

Frequently Asked Questions

What happens if I don’t do anything about a fairy ring growing in my yard?

If you have a fairy ring and you simply leave it alone, nothing terrible will happen. You might notice fluctuations in how green or brown your grass is, but only right at the outer edge of the ring. For most homeowners, having a fairy ring of mushrooms is a cosmetic concern because your once evenly green lawn now has a circle of mushrooms growing in it. But don’t worry, the mushrooms are short-lived and will decompose back into your lawn. You can expect them to reappear, in slowly expanding circles, around the same time every year.

Are fairy ring mushrooms edible or poisonous? 

Most people are curious about mushrooms and wonder if they are poisonous. Many people even assume that every mushroom is poisonous. In fact, there are at least 60 different species of mushrooms that are capable of forming fairy rings. Of these, some are highly toxic, and a few are edible.

Unless you are a mushroom foraging expert and can accurately identify the species of mushroom you’re looking at, you should NEVER sample a wild mushroom to find out if it’s poisonous. Don’t allow children to play with fairy ring mushrooms. And if your dog has an adventurous appetite, keep it away from wild mushrooms as well, just to be safe.

How did this fairy ring get into my yard in the first place?

All mushrooms start with a single spore. The spore probably blew over from another mature fairy ring, found a favorable environment in your yard, and started to grow. You wouldn’t notice anything for the first year or so, and then, suddenly, when all the growing conditions are just right, the mushrooms pop out of the ground, seemingly out of nowhere.

Is there anything I can do to prevent fairy rings in my yard?

Unfortunately, there isn’t much you can do to prevent a wind-blown mushroom spore from entering your yard. Since you can’t see the beginning of a fairy ring because it all happens underground, you won’t even know that fungus has taken hold until you see the fruiting bodies – the mushrooms that appear above ground. The best thing you can do is take good care of your lawn and garden. A healthy landscape is also a resilient landscape.

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