Q. Why is there a mushroom-like growth around the trunk of my tree speading out along the ground?
Dear Jo Ellen,
The mushrooms are a clear indication that the tree has deadwood present in the root system, which is rotting or decaying. If the foliage continues to look green and healthy, this may not be too much of a problem, but ultimately this fungus growth may cause weakening of the tree, and cause it to break or fall. As far as stopping the mushrooms from appearing, this may be difficult to do unless you remove the fungal food source, which is the rotting wood or roots. Remove the mushrooms by hand when they appear, and then dig to a depth of about 12 inches and a spread of about 18 inches to remove the fungal mat. Fill in the hole with soil free of organic matter or compost. Be careful not to overwater. If the ground is drier, the fungi are less likely to grow. Aerate the soil around the tree. Good drainage and circulation help prevent the growth and development of fungi. Clear the area around the tree of plant debris and organic matter. Rake up fallen leaves and cut grass from around the trunk. Decaying plant matter makes a humid, nutrient-rich environment for mushroom growth. Fertilize with a nitrogen fertilizer at 1 pound per 1,000 square feet. Nitrogen will make the soil less hospitable to fungal growth. Mushrooms already growing in the soil may die off after application. You might want to have an arborist take a look to determine exactly what type of fungus this is, or you might consider taking a sample of the mushrooms to the Cooperative Extension Service for analysis and further advice. The Philadelphia branch is located at 2 Penn Center Plaza, Suite 200. The telephone number is 215-471-2200.