Why are mushrooms popping up in my yard?
By Georgianne Messina
This article will not identify poisonous versus edible fungi. Identification of mushrooms should be done by experts -UCCE Master Gardeners are not mycologists either professionally or as hobbyists. Mis-identification of mushrooms has had lethal effects on humans and pets.
***Correction 2/2/23 - Mushrooms aid in the decomposition of matter. They secrete (not excrete) enzymes that begin the process of decomposition.
This winter, there seems to be no avoidance in spotting a multitude of mushrooms growing in yards, park trails, and occasionally in houseplants. Are we being invaded by UFOs (unidentified fungal objects) more than last year? It seems like it. Why? Are these mushrooms harmful to people and pets? Should I get rid of them and how can I dispose of them in a safe manner?
Why are there so many mushrooms this year?
Mushrooms – good or bad?
The appearance of mushrooms in a garden or yard brings anxiety to many. Though wild mushrooms can be harmful, if ingested, they also are essential supporters of plants such as native oaks, pines, and conifers. They may serve as indicators of plant or soil health.
Are Mushrooms Beneficial?
While mushrooms are beneficial for many reasons, we will focus on just two in this blog. Please note that mushrooms and fungi will be used interchangeably.
- Photo submitted to our Help Desk-Author photo (Palomares Hills) – mushrooms on decaying birch roots
- R Photo:Jerrold Turney, Los Angeles County; Dept. of Agricultural Commissioner L Photo: adeleon (Palomares Hills)
Are Mushrooms Harmful?
This article will not identify poisonous versus edible. Identification of mushrooms should be done by expert mycologists. UCCE Master Gardeners are not mycologists either professionally or as hobbyists. The misidentification of mushrooms has had lethal effects on humans and pets.
As East Bay Regional Parks (EBRP) website points out: “The Bay Area is home to two of the world's most toxic mushrooms. Amanita phalloides (the Death Cap) and Amanita ocreata (the Western Destroying Angel). Both are robust, handsome mushrooms that grow near oak trees, and both contain lethal toxins.” The article goes on to say that these two mushroom species are responsible for most of the mushroom poisonings; however, Galerina and Lepiota species are poisonous as well and are found in the Bay Area."
Text and photos by Trent Pearce, Naturalist, Tilden Nature Area
More photos can be found on the EBRP website.
Erring on the side of caution seems to be the best way to approach an unidentified, wild mushroom.
How do I safely remove and dispose of a UFO (unidentified fungal object)?
To remove the mushrooms, carefully rake them up in a small pile or dislodge them manually (wear nitrile gloves). Place the mushrooms in a paper or compostable bag and place it in the green bin. Discard the gloves, wash your hands after this activity, keep pets and children away from the area while you are working. Again, best to err on the side of caution since you do not know the type of mushroom you are dealing with.
Are Mushrooms Harmful to Children?
Wild mushrooms certainly have the potential to be harmful. From November 2016 through January 2018, there were about 1038 cases of mushroom poisoning. Of those cases, 433 (41.7%) were children under six years of age*. Eating poisonous mushrooms can cause abdominal pain, cramping, vomiting, diarrhea, liver damage, or death. Anyone who develops symptoms after eating wild mushrooms should seek immediate medical attention. People who develop these symptoms should immediately contact the California Poison Control System at (800) 222-1222 or their health care provider
Are Mushrooms Harmful to Pets?
Again, wild mushrooms DO have the potential to be harmful to pets. Dogs are affected differently than cats. Some mushrooms have a fishy odor which attracts pets.
According to the UC Davis School of Veterinary Medicine,” It is safest to assume that all wild mushrooms that your dog encounters are toxic.“ If your pet may have been poisoned by mushrooms, try to get a sample of the same mushroom or mushrooms from where they were found. This will help aid in identification.
Place any available material in a paper bag or waxed paper, not plastic, and refrigerate until it can be examined. Note where the mushrooms were collected in case the mushrooms may have been contaminated by uptake of pesticides or heavy metals from lawns, roadsides, or industrial areas.
Symptoms are delayed after ingestion (up to 12+hours). Do not wait for the mushroom to be identified or wait for symptoms to start., call your veterinarian or contact an emergency veterinary hospital as rapid treatment is critical.
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Mushrooms in lawns
Armillaria Root Rot Management
East Bay Regional Parks - Toxic Mushrooms
California Poison Control System
Stanislaus County Master Gardeners - Magical Mushrooms
Mycological Society of San Francisco
Toxic Fungi of North America
Mushroom Poisoning in Dogs
Mushrooms may mean healthy soil