More Houseplant Mushrooms

Question:
I seem to have mushrooms in my hibiscus, and I can't figure out where they came from, or how to get rid of them. The hibiscus is strictly an indoor plant, and has been for about 4 or
5 years (ever since it grew too big to move outdoors in the summer). It's been in the same pot - and the same soil - at least since then. A few weeks ago, I noticed some small yellow mushrooms growing in clusters in the soil at the base of the pot. They grow fast, and no matter how often I pull them out, they keep coming back. I know it's been very humid lately, and I do try to let the soil dry out between waterings, but it doesn't seem to help. Since the plant lives indoors, I'm not sure where they came from - no other plants in the house seem to have them, fortunately - and I'm at a loss as to how to permanently get rid of them. Any suggestions you have would be greatly appreciated! It's a lovely old plant, and I'd like to keep it around for a bit longer.

Answer:

Believe it or not, I have actually gotten this question before. Back in July a woman wrote, describing similiar mushrooms growing at the base of a houseplant she too had had for a number of years. You can click on a link to that entry here.

The important thing for you to know is that these mushrooms are not going to kill your hibiscus. They do promote the further degradation of your soil, and in a container that is not the greatest thing, but the mushroom spores themselves will not harm the plant. As you know, however, they will continue to spread and put up mushrooms. I do not know if there is a fungicide on the market that is used to combat these mushrooms in particular. Taking more of a naturalistic approach, I would recommend repotting your hibiscus. If it is 4-5 years old and has never been repotted then the plant will benefit from fresh soil that has better soil structure and more nutrient value. Given the mushroom situation, try and remove as much of the old soil as possible before applying the fresh soil. Repot your hibiscus into a larger container that is a couple inches greater in diameter. It is best to repot hibiscus in the spring, but if you feel the need to do it now I do not think that is going to shock the plant too much. When repotting, do your best not to expose the roots to direct sun or extremely hot temperatures as this may stress the plant, and we obviously want to try and avoid that. Good luck and let me know if you need further help.

Houseplant Mushrooms?

Question:
Can you do me the kindness of identifying the attached mushroom? I'm not planning on eating them anyway, but I was curious to find out what they are, in the hopes that might give a clue as to how they arrived in my apartment. I live on the 24th floor of a high-rise in Manhattan, so the spores were probably either carried in by a fly, or they've been dormant in the dirt for a very long time. They appeared suddenly in a 30-year-old Thanksgiving cactus that I only water once every two weeks, so I'm really amazed that the conditions encouraged them.

Answer:
I must admit that I am not as much of a mycologist (one who specializes in fungi, etc.) as a horticulturist but just the same I think I was able to identify your new findings. Believe it or not there is a type of mushroom that is commonly found growing among houseplants. It used to be called Lepiota lutea, but the scientific name has been changed to Leucocoprinus birnbaumii. Either way this fungus is commonly called the yellow houseplant mushroom. The spores were most likely in the soil, or perhaps in new soil if you transplanted your Thanksgiving cactus (Schlumbergera truncata) any time recently. I am not sure how toxic or not these fungi are, but I think it is safe to say that they are not edible. If you choose to remove them you can simply pull them out with your hands without any risk of skin rash or irritation.

If you do a Google search for “Leucocoprinus birnbaumii” you should be able to find some interesting and credible resources online. I found one page from the University of Wisconsin that was very informative. I often mention to those who are searching for plant information that knowing and using the scientific name (of plants, bugs, fungus, etc.) when doing internet searches tends to lead you to more credible sources of information. Obviously in your case the same holds true.