Master Gardener: Mushrooms in my flowerbed |

Master Gardener: Mushrooms in my flowerbed

Vicky Barney
For Steamboat Pilot & Today

In past years, small mushrooms have popped up here and there in my grass. They have not formed circles (called “fairy rings”) and have been easy to remove. I do not recall seeing them in my flowerbed until this year.

Recently, I noticed mushrooms growing among some of my flowers. They are growing beside flowers planted two summers ago and in ground cover established several years earlier. Most are a bit larger than mushrooms previously seen in my grass, except for a few enormous ones (3 inches in diameter) covering the base of a tall penstemon. The penstemon plant beside it had none. What is going on?

In online research, I learned mushrooms are the fruiting body of a fungus that reproduces by spores developed in the cap. Other online resources confirmed they are not harmful to plants, are a sign of healthy soil and improve a plant’s health.

Garden blogger Corey Leichty has a detailed article on the subject: “Why soil grows mushrooms and how to get rid of them.”

Mushrooms require a food source, moisture and cool temperatures in order to grow. While their appearance indicates a healthy garden — soil with lots of organic material — they also may be a sign of a garden out of balance.

Too much or the wrong mulch, an excess of dead plant material and dead tree roots in the soil all contribute to mushrooms’ food source. Overwatering is also conducive to their growth, as is soil cooled by lower temperatures, shade and excess mulch.

In my situation, I suspect I have been overwatering in shady areas. An overabundance of food is also likely, as the affected area is under trees whose leaves are not raked. Lastly, when I look at the pattern of the mushrooms’ appearance, I wonder if dead tree roots under the soil are providing additional organic material.

My flowers are thriving, but I have decided the mushrooms must go. They may sicken my dog if she eats them, even if they are not poisonous. Wearing gloves, I have picked and bagged the mushrooms, disposing of them properly.

Next will be to let the soil dry out and avoid adding organic material in the area. The mushrooms may appear again as the fungus is in the soil, but I will wait and see if they return. If they do, I may add nitrogen fertilizer, put soap and water in the soil, or make other changes to the environment. It is another gardening adventure.

Vicky Barney gardens for wildlife and is a member of the Master Gardener Class of 2011.

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