If You See a Yellow Mushroom in Your Houseplant, This Is What It Means

Don't panic just yet!

When you’re a plant parent, you’re consistently monitoring the health of your houseplants. From scouring for soggy roots to examining yellow leaves, you’re always on the lookout for signs your beloved plants are unhappy.

But there’s one sign that’s particularly hard to decode: mushrooms in the soil. These mysterious bright yellow fungi can look especially dangerous. But do they pose any real threat? Here’s everything you need to know, from the species of mushroom to how to get rid of them.

What Is the Yellow Mushroom in my Houseplant?

Plantpot Dapperling Fungus Leucocoprinus Birnbaumii (also Known As Lepiota Lutea) Is Quite Common In Potted Plants And Greenhouses.MollyNZ/Getty Images

According to Iowa State University’s Horticulture and Home Pest News, Leucocoprinus birnbaumii is the most common species of yellow mushroom in houseplants.

Sometimes called the “yellow houseplant mushroom,” “yellow parasol” or “flower pot parasol,” it’s usually one to three inches tall. Their ovular or bell-shaped caps can grow up to two inches in diameter, and they can sprout singly or in clusters.

Why Is There a Yellow Mushroom in my Houseplant?

These thrive in warm, humid environments, so they can appear in houseplants or greenhouses year-round. And while you might assume their presence indicates overwatering, this isn’t always the case.

According to the website Garden Know How, the real culprit is usually the potting mix itself: “The spores that are the cause of mushrooms growing in houseplant soil [are] normally introduced by contaminated soilless mix.” Humans, pets and even air can also sometimes bring spores in from outside.

Is the Yellow Mushroom in my Houseplant Dangerous?

Plantpot Mushroom growing in an indoor potted plantMichelle Lee Photography/Getty Images

No. The yellow mushrooms are typically not harmful to the plant.

According to Dan Gill, the Times-Picayune garden columnist at Nola.com, the fungus that makes the mushroom is “just decaying the organic matter in the potting mix.” Gill recommends ignoring it.

The mushrooms actually may support the health of your houseplant. As TheSill.com explains, the mushrooms perform many vital functions. They absorb ammonium in the ecosystem, which “helps solubilize and mobilize metals and phosphates that are essential for your plant.” And they communicate threats to the plant through their mycelium networks.

Per TheSill.com: “Nearby plants will boost their own innate defenses [against insects] if they hear over the mycelium that one of their neighbors is being attacked.” This means that mushrooms provide essential nutrients and valuable intel to the houseplants.

Still, there’s one excellent reason to remove the yellow mushrooms: they can be poisonous to pets and humans. Horticulture and Home Pest News suggests removing the mushrooms as soon as they appear if “pets or small children reside in the home.”

How Can I Get Rid of the Yellow Mushroom in my Houseplant?

Take the following steps, as outlined by Garden Know How.

  1. Remove the caps: Do this as soon as possible to prevent the mushrooms from releasing spores and spreading.
  2. Change the soil: Remove the plant from the pot, shake off the roots and replant it in fresh, uncontaminated soil. If you cannot repot the plant for whatever reason, at least remove the top two inches of soil.
  3. Add fungicide. While Horticulture and Home Pest News claims fungicide doesn’t affect mushrooms, other sources suggest some products may work.
  4. Alter the conditions: Try to lessen the humidity or lower the heat in your home to prevent mushrooms from sprouting.

While none of these methods are foolproof, they’ll decrease the likelihood of a mushroom invasion. Still, the mushrooms are only poisonous if ingested, so you can always simply place the houseplants beyond reach.