Tree roots with mushrooms - Ask Extension
Tree roots damaged by mower and noticing mushroom growth along roots.
Tree is believed to be red maple and is abt 35+years old.
How can I help this ...
Knowledgebase
Tree roots with mushrooms #948357
Asked November 10, 2026, 9:17 PM EST
Tree roots damaged by mower and noticing mushroom growth along roots.
Tree is believed to be red maple and is abt 35+years old.
How can I help this Tree survive? Do I mulch, spread soil. Use cover plants,etc. Please help
Baltimore County Maryland
Expert Response
Using groundcovers instead of lawn under trees (and in the tree's root zone) is one good way to avoid harming the roots in this fashion, and over time, the lawn close to a tree tends to decline anyway due to the shade and root competition. You can find some groundcover species candidates on the linked page, but it's too late for any roots with significant damage and mushroom growth.
Mushrooms growing out of wood, whether a trunk, branch, or surface root, are not a good sign. Although mushrooms growing in the middle of a lawn are usually harmless because the fungus producing them is feeding on already-dead organic matter in the soil (or is growing in association with live turf roots as a beneficial organism), those that grow on wood indicate that wood decay is present. The mushrooms pictured look like they might be one of the active wood decay species (fungi that infect live wood rather than those breaking down wood that is already dead), such as Armillaria, but it's hard to tell.
Decay has been taking place for some time by the time mushrooms appear, and unfortunately such conditions are irreversible. Trees can sometimes successfully compartmentalize (wall-off) decay internally so it doesn't spread, but it's nearly impossible to tell if that is working by looking at the exterior of the tree. If only one or two roots are affected by decay fungi, then the issue might not be that significant, but it can be hard to tell where fungal spread has occurred until mushrooms are produced later.
Any tree health concerns should be evaluated by a certified arborist or licensed tree expert. While they cannot treat or cure every condition, and wood decay cannot be remedied (whatever tissues were lost cannot be regrown), they can help narrow-down a diagnosis and look for sources of tree stress that might be able to be alleviated. Individual tree roots can be lost without necessarily dooming or destabilizing the entire tree, but we defer to the assessment of a professional who can examine the tree in person. This time of year, with leaves falling, it can be harder to determine how healthy the canopy looks, so while it's fine to get an arborist's assessment now, they might have an easier time judging tree health once the canopy is full again in late spring.
Miri
Mushrooms growing out of wood, whether a trunk, branch, or surface root, are not a good sign. Although mushrooms growing in the middle of a lawn are usually harmless because the fungus producing them is feeding on already-dead organic matter in the soil (or is growing in association with live turf roots as a beneficial organism), those that grow on wood indicate that wood decay is present. The mushrooms pictured look like they might be one of the active wood decay species (fungi that infect live wood rather than those breaking down wood that is already dead), such as Armillaria, but it's hard to tell.
Decay has been taking place for some time by the time mushrooms appear, and unfortunately such conditions are irreversible. Trees can sometimes successfully compartmentalize (wall-off) decay internally so it doesn't spread, but it's nearly impossible to tell if that is working by looking at the exterior of the tree. If only one or two roots are affected by decay fungi, then the issue might not be that significant, but it can be hard to tell where fungal spread has occurred until mushrooms are produced later.
Any tree health concerns should be evaluated by a certified arborist or licensed tree expert. While they cannot treat or cure every condition, and wood decay cannot be remedied (whatever tissues were lost cannot be regrown), they can help narrow-down a diagnosis and look for sources of tree stress that might be able to be alleviated. Individual tree roots can be lost without necessarily dooming or destabilizing the entire tree, but we defer to the assessment of a professional who can examine the tree in person. This time of year, with leaves falling, it can be harder to determine how healthy the canopy looks, so while it's fine to get an arborist's assessment now, they might have an easier time judging tree health once the canopy is full again in late spring.
Miri
