Garden Help Desk: Dead tree roots likely cause of lawn mushrooms
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- Because it’s not unusual for there to be both harmless and toxic mushroom species in a single genus, you shouldn’t assume attractive mushrooms in a lawn are edible.
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- Mushrooms in lawns won’t harm the lawn. They are most common when soil moisture or humidity are high and temperatures are mild or warm.
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- Handpicking and discarding is one way of managing mushrooms in lawns.
Since September, when it started raining, I’ve been having a problem with white mushrooms in my backyard. They have mostly been growing within 6 feet of a fence along the south side of my yard, but there also is an area further from the fence where they grow. Sometimes they grow singly, but other times they grow in bunches that are close to each other. I have had mushrooms in the yard before, but nowhere near as many as this year.
Is there a possibility that decomposing tree roots could be related to this problem? There were several trees in the area that were cut down years ago, and since the mushrooms seem to grow in a line at times, it makes me wonder if that could be a cause.
I’ve spent a lot of time picking them (nearly every day) and I’m wondering if there is a better way to deal with them. Is there any way to prevent them?
Mushrooms like the ones in your photos are common in lawns. They aren’t a sign that you’ve done something wrong; they just indicate that there is dead or decaying organic matter in the soil where you see the mushrooms.
You’re right to suspect the tree roots that were left after the tree removal. Fungi feed on organic matter. Buried construction debris, compost that wasn’t completely broken down and dead tree roots are three common food sources for underground fungi in lawns. In your case, the fungi have been breaking down — or feeding on — the tree roots. Then, when conditions were favorable (higher soil moisture and warm temperatures), the fungi started producing fruiting bodies — the mushrooms.
The underground fungi and the mushrooms don’t harm the lawn, so there is nothing extra you need to do to “protect” your lawn. Just give routine good lawn care next year: adequate fertilizer and deep, infrequent watering.
Unfortunately, there aren’t any chemical controls that are effective for preventing the mushrooms, although you’ll find products and services for sale that claim to do just that. The usual options for managing mushrooms in the lawn are handpicking or simply ignoring them.
Meredith Seaver is a USU Extension horticulture assistant.
