I don’t know if you have noticed, but we have been getting a lot of rain lately. And when I say “a lot” I mean “A LOT” as in several inches over the last few weeks. Okay, the several inches may be in isolated areas, but we have had A LOT of rain. This leads to all sorts of problems. A slow down at the car wash, the lawn care services, the pools… the pools that appear in your backyard… and mushrooms popping up everywhere!
What you see in the yard is actually the “fruit” of a fungi. When they appear it usually indicates that there is some decaying tree stumps or roots in the soil. Or even some mulch. I spoke with Black Hawk County Horticulturist Bryan Foster and he mentioned that sometimes morels will even grow in mulch! Now be careful what you step on while looking for those elusive fungi.
While mushrooms, or toadstools, in the lawn can be annoying, they usually don’t cause any harm to turfgrass. There is really nothing that can be applied to the soil to prevent them from emerging. Just mow them off or rake them and throw them away as they appear. When it gets warmer and drier they will stop appearing. When the stump, root or whatever the food source is has finally rotted away, the mushrooms with disappear, too.
Now there is another type of yard fungi that can cause some trouble to the lawn. These are the ones that can create fairy rings in your yard.
This type of fungus can be seen from a distance since it tends to create a circle or arc of dark green or brown grass. Fair ring circles can be many feet in diameter and tend to grow outward slowly.
It used to be thought that they were caused by fairies dancing in a circle in the middle of the night, but in reality they are caused by an assortment of fungi feeding on dead, organic matter in the grass and soil. As the fungi break down this matter, the nutrients are released leading to a darker area of turfgrass. If the structure is very dense it may interfere with the movement of water to the roots of the turfgrass and circles of dead grass may be seen. And some fairy rings produce mushrooms in the circle, mainly late summer or early fall.
Fairy rings are difficult to get rid of and fungicides are not very effective. Removal of the soil in the ring is the primary means of control, but doesn’t always work and may not be very feasible if the fairy ring is large.
You can find out more about Iowa’s Mushrooms and other nonflowering plants by clicking here.
Don’t eat any mushrooms unless you are absolutely sure about what you are about to put into your mouth. Contact your local Iowa State Extension office for more information.