Recently poisonous mushroom started growing in my yard. I have these questions: Could they have grown from spores in my commercial compost? Are they a risk to my dog or other animals? How do I get rid of them? Thanks so much for your advice! Kathy
Benton County Oregon mushrooms
These Amanita muscaria mushrooms are symbiotic with conifer and other plant roots. This relationship is called mycorrhizal. They do not originate from mushroom compost. They either came in on the roots of plants used in landscaping or from aerially distributed spores from other places. This is a very common mushroom in Oregon.
Mushrooms grow from masses of underground cells called mycelium. The mushroom is the part of the fungus that distributes spores.
To get rid of them you can either pick them as they grow up through the soil, or you would have to remove all of your landscape plants, including trees, which are connected to the underground mycelium. The fungus is actually helping your plants grow by shuttling soil nutrients into the roots. You should consult with a veterinarian to determine if this species is harmful to pets.