Asked September 27, 2019, 7:22 PM EDT

I am battling mushrooms all over the yard. Can you suggest something that is safe for animals and humans that will kill off the spores? They are very thick under the Vinca groundcover, so I don't want an overall spray of any kind. Please advise. Thank you!

Washington County Oregon

1 Response

Thank you for choosing Ask an Expert to find information about the mushrooms in your yard. Minnesota Extension agent, Pat Mack, has a great explanation. Here he is talking about mushrooms growing in association with a tree root, but they can grow on any organic matter in our soil.

“The mushrooms are digesting the decaying organic matter found in the dead tree roots. There is little you can do to prevent their growth because they grow in the ground for years, decomposing thatch, old roots, tree stumps, or pieces of lumber left by the contractor.

Every time the weather is wet for a long period, they will produce their fruiting structures. These are the mushrooms you see. If you don't like the looks of them, or if you are worried about children or animals eating them, rake up and destroy the mushrooms.

Usually mushrooms grow in a helter-skelter fashion in the lawn. There is a type that comes up each year forming giant rings or circles of mushrooms. Each year these rings grow in diameter as the mushroom strands grow through the soil. These are called fairy ring mushrooms.”

As Mack states, there is no product or method to really keep these from coming up. Raking them out of lawns and beds or simply collecting them and disposing of them in the yard debris is the recommended method. Our warm, wet fall weather has encouraged mushrooms of many types to pop up all over the Portland Metro area. Additional information from the Oregon Extension Service can be found here:

For a one-to-one chat about this issue, you can call the Washington County Master Gardeners at 503-821-1150 (Monday through Friday-- 9:00 am to noon and 1:00 pm to 4:00 pm).

Have a great fall,