What Are Those Yellow Mushrooms in My Plant Pot?

Do you have yellow mushrooms in your potted houseplant?

I receive a lot of emails from people questioning this strange mycological manifestation that suddenly graces their plant pots. To these folks I say: you've just met Leucocoprinus birnbaumii, the yellow houseplant mushroom!

Leucocoprinus birnbaumii (also known as Lepiota lutea) is quite common in potted plants and greenhouses. This species is considered inedible, although the exact toxicity is unknown. So don't eat them, no matter how candy-like they appear!

Yellow mushrooms in a potted houseplantThis mushroom pops up as a result of contaminated potting soil or mulch. The mushroom spores infect the soil, and are widely distributed as it's packaged and shipped. Infection can happen at any point, from a contaminated ingredient from a factory or farm to spores on the clothes of an employee.

Let's take a look at how to identify these yellow mushrooms and what to do about them. We'll start with identification, move on to what to do about them, and end with an infographic summary.

Click here for more information about types of mushrooms in general.



Leucocoprinus birnbaumii Identification


Indoor identification of Leucocoprinus birnbaumii is pretty easy. If you have small yellow mushrooms growing in a potted houseplant, chances are you have this species.

That said, here are some basic facts:

  • Bright to pale yellow in color throughout, including the inner flesh.
  • Cap is a 1 - 2 inches tall and oval when young, becoming more bell-shaped with age. The cap is also textured with scales or dots.
  • Leucocoprinus birnbaumii - yellow houseplant mushroomThis is a gilled mushroom, although the gills do not attach to the stem.
  • The stalk (or stipe) is a few inches tall and has a ring around it, although this ring often disappears with age. The ring is a remnant of the partial veil, a thin layer of tissue that protects the gills as they are developing.
  • Prefers wet soil and hot weather.
  • The spore print is white.
  • These are saprotrophic mushrooms, meaning they feed on dead organic material. Thus they won't hurt a living, healthy houseplant.


Know Your Yellow Mushrooms - Now What?


What do you do about these yellow mushrooms?

First off, know that they will not hurt your houseplant. They also won't disturb you, your kids, or your pets unless they're eaten. If there's no danger of anyone eating them, it's perfectly fine to just leave them where they are and enjoy their beauty.

However, there is a chance that spores from Leucocoprinus birnbaumii will travel to your other plants and infect them as well. So if you don't want a house full of yellow mushrooms, or if you fear kids or dogs eating them, you can try one of the following to get rid of them:

  • Remove the plant from the house - Either put it outside or get rid of the plant entirely. No doubt the simplest solution.
  • Attempt spore removal - Pick off all visible mushrooms from their base and replace the top few inches of potting soil. This may or may not work, depending on how deeply the fungus has grown into the soil.
  • Replace the soil entirely - As a last resort, you can try replacing the potting soil entirely. Remove the plant and try to get as much dirt as possible off its roots. Know that by doing this you may stress the plant, and the mushrooms could very well come back anyway.

Truthfully these mushrooms are very hard to get rid of. As the spores and mycelium (the vegetative growth of the fungus) are deeply settled in your plant pot and roots, it's difficult to remove them entirely.

Yellow houseplant mushrooms - Lepiota luteaThe plant should be removed if there's a chance the mushrooms will be eaten by pets or children. Otherwise you may want to just leave them be, and enjoy the splash of color. They won't hurt you by sitting there, and they make a great conversation piece.

I hope you've enjoyed learning about Leucocoprinus birnbaumii, the yellow houseplant mushroom. The next time one pops up in your plant pot, you'll know what it is!


Infographic on how to get rid of yellow mushrooms

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All photos on this page taken by Christine Greenspan.