Garden Detective

Mushrooms dangerous to sniffing dogs?

What are these strange brown mushrooms? They look like haymaker’s mushrooms, a common lawn fungi.
What are these strange brown mushrooms? They look like haymaker’s mushrooms, a common lawn fungi.

Experts tackle readers’ garden questions.

Q: I have these mushrooms growing in my backyard. After they mature a bit more, they appear to turn in a bit like umbrellas and they get a chocolate dark brown. My dogs like that area to go to the bathroom. Are these mushrooms dangerous for them to sniff?

Raul Moreno, Sacramento

UC Master gardener Carmen Schindler: Definitive mushroom identification relies on characteristics of the cap, as well as the stalk, gills and spores, which are not shown in the photo. However, the mushrooms’ size and features are consistent with Panaeolus foenisecii, also referred to as haymaker’s mushrooms. They are very common and often found in lawns.

Eating mushrooms collected outdoors can be very risky. Many poisonous mushrooms look and taste like those that are safe to eat and there is no easy way to tell the difference between safe and unsafe mushrooms.

Because small children tend to put anything, including mushrooms, in their mouths, all obvious fungal reproductive structures should be removed from the yard before allowing a child to play there. In addition, children should be taught to never touch or taste mushrooms found outside.

Pets also can be harmed by ingesting poisonous mushrooms. I was not able to find any information regarding the danger to dogs when sniffing mushrooms, but dogs have a tendency to eat anything, so it is important to take precautions and remove the mushrooms as soon as possible. Make it a part of your weekly “doggy-doo-doo-pick-up” activity. The American SPCA website offers a list of toxic plants, as well as numerous articles related to mushrooms and dogs.

Mushrooms found in lawns often develop from buried scraps of construction lumber, dead tree roots or other organic matter. The fungi that produce these mushrooms are beneficial because they decompose organic matter in the soil, making nutrients available to other plants. These mushrooms are usually harmless to grasses; however, some people consider them unsightly or want to get rid of them because young children play in the area. Remove mushrooms growing from buried wood or roots by picking the mushrooms as they appear or by digging out the wood.

Mushrooms in lawns also are commonly associated with over-irrigation or poor drainage. Removing excess thatch and aerating the soil to improve water penetration in the lawn can help.

For more information on nuisance fungi, check out the University of California (UC), Integrated Pest Management website at

Carmen Schindler is a UC Cooperative Extension Master Gardener for Sacramento County.

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Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties. Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to h& Please put “Garden Detective” in the subject field and include your postal address. To contact UC Extension directly, call:

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