Mushrooms Are Growing Near My Tree—Should I Be Concerned?
What mushrooms may—and may not—tell us about the health and structural condition of a tree.
Mushrooms Are Growing Near My Tree—Should I Be Concerned?
Finding mushrooms near a tree can be concerning—especially when they appear suddenly, return year after year, or grow directly from the trunk or roots.
The short answer is: sometimes—but not always.
Mushrooms are evidence of fungal activity, but their presence alone does not tell us whether a living tree is being harmed. Some fungi decompose mulch, buried wood, old roots, or other organic material in the soil. Others may be associated with decay in living or dead portions of a tree.
The type of fungus, where it is growing, its relationship to the tree, and the overall condition of the tree all help determine its significance.
What Is a Mushroom?
The mushroom we see above ground is only the visible reproductive structure—or fruiting body—of a much larger fungus.
Much of the fungus may exist out of sight as a network of microscopic strands growing through soil, mulch, roots, or wood.
A mushroom may appear for only a short period when moisture, temperature, and other environmental conditions are favorable. The visible mushroom may disappear, while the underlying fungus remains.
Removing the mushroom therefore does not remove the fungus itself.
Location Matters
One of the first questions to ask is:
Where are the mushrooms growing?
Mushrooms scattered throughout mulch or a lawn may be decomposing organic material and may have little or no direct effect on the living tree.
Mushrooms growing from an old stump, buried wood, or decaying roots may be part of the natural decomposition process.
Fungal growth may deserve closer attention when it is:
Growing directly from the trunk
Attached to the root flare
Emerging from large structural roots
Concentrated around the base of the tree
Appearing repeatedly in the same location
Associated with cavities, damaged bark, or visible decay
Accompanied by canopy thinning, branch dieback, or reduced growth
Location alone does not provide a complete diagnosis, but it can offer important clues.
UFT INSIGHT
A mushroom is evidence of fungal activity—not a complete diagnosis. Its identity, location, relationship to the tree, and the tree’s overall condition determine its significance.
Mushrooms in Mulch Are Often Part of Natural Decomposition
Organic mulch contains wood, bark, leaves, and other plant material that naturally decomposes over time.
Fungi are an important part of this process.
Mushrooms growing throughout a mulch bed may simply indicate that fungi are breaking down organic material and contributing to nutrient cycling. Their appearance may be encouraged by rainfall, irrigation, warm temperatures, shaded conditions, or moisture retained within the mulch.
In many cases, mushrooms growing only from mulch are temporary and do not require treatment.
If desired, the visible mushrooms can be removed for appearance or to reduce the chance that children or pets may come into contact with them. However, removing the mushrooms does not eliminate the underlying fungal activity.
Mushrooms Near a Tree Do Not Always Mean the Tree Is Decaying
A mushroom growing near a tree may be associated with:
Mulch
Buried wood
Old construction debris
Decaying roots from a previously removed tree
Dead portions of the tree’s root system
Naturally occurring organic matter in the soil
Living tree roots
Decay within major roots, the root flare, or lower trunk
Because several possible sources may exist below ground, proximity alone does not prove that the living tree is affected.
The mushroom’s identity and exact point of attachment can be important. A mushroom growing several feet from a tree may still be associated with a root—or may be completely unrelated to the tree.
When Fungal Growth May Be More Concerning
Some fungi are associated with the decay of wood in roots, trunks, or branches.
Decay can affect the strength of wood, but the presence of decay does not automatically mean that a tree is likely to fail or must be removed.
The significance depends on factors such as:
The type of fungus
The location and extent of affected wood
Whether important roots or structural tissues are involved
The tree species
The size and condition of the tree
The amount of healthy wood that remains
The tree’s location
What could be affected if a branch or the tree were to fail
Fungal growth near the root flare or major roots may be especially important because these areas contribute to the tree’s support and stability.
A tree with a full, green canopy may still contain structural decay. Tree health and tree risk are related, but they are not the same.
Do Not Rely on the Mushroom Alone
A mushroom can provide useful information, but it should be considered together with the entire tree and its growing environment.
Look for additional changes such as:
Increasing canopy thinning
Progressive branch dieback
Reduced annual growth
Smaller-than-normal leaves
Premature fall color or early leaf drop
Cavities or damaged bark
Cracks in the trunk or major branches
Loose or separating bark
A buried or damaged root flare
Changes in tree lean
Soil lifting or cracking near the base
Construction, excavation, or root disturbance
Changes in drainage or prolonged soil saturation
The absence of visible canopy decline does not necessarily rule out decay. Likewise, canopy decline does not prove that fungal decay is the underlying cause.
Should I Remove the Mushrooms?
Removing visible mushrooms is generally optional unless they create a concern for children, pets, appearance, or use of the property.
If you remove them:
Wear gloves
Place them in a bag for disposal
Avoid mowing over unknown mushrooms
Wash your hands afterward
Do not eat any mushroom unless it has been identified as safe by a qualified mushroom expert
Removing or mowing the mushroom does not treat decay or eliminate the fungus growing within soil, roots, or wood.
Before removing unusual fungal growth associated with a tree, consider taking photographs. Mushrooms may disappear quickly and may not be present when the tree is later evaluated.
Take Photos Before the Mushrooms Disappear
Clear photographs can provide useful information if the mushrooms are temporary.
Try to photograph:
The top of the cap
The underside of the cap
The stem or attachment point
The entire group of mushrooms
The exact location where they are growing
The trunk, root flare, or root associated with them
The entire tree and surrounding site
Including an object for scale may also be helpful.
Do not disturb the mushroom before taking photographs if it can be avoided. The attachment point and growth pattern may provide useful information.
Should I Apply a Fungicide?
Fungicide is not an automatic solution for mushrooms growing near a tree.
If a fungus is decomposing mulch or buried organic material, treatment may be unnecessary.
If fungal growth is associated with decay in roots, the trunk, or major branches, removing the visible mushroom or applying a surface treatment generally does not restore wood that has already decayed.
The first step is understanding:
What the fungus may be
What material it is growing from
Whether the living tree is affected
Whether structural tissues may be involved
Whether management or further evaluation is appropriate
Treatment should follow diagnosis—not replace it.
When Should I Call an Arborist?
Consider having the tree evaluated when mushrooms or other fungal structures are:
Growing directly from the trunk
Attached to the root flare or major roots
Appearing repeatedly in the same location
Associated with cavities, cracks, damaged bark, or visible decay
Accompanied by canopy thinning or increasing branch dieback
Present near a tree that has experienced construction or root damage
Associated with a noticeable change in tree lean
Growing around a large tree near a home, driveway, road, play area, or other frequently occupied space
An arborist can evaluate the fungal growth together with the tree’s canopy, trunk, root flare, visible roots, surrounding soil, site history, and potential consequences if failure were to occur.
In some situations, continued monitoring may be appropriate. In others, additional investigation, management, a more detailed tree-risk assessment, or removal may need to be considered.
The Bottom Line
Mushrooms near a tree are not automatically a reason for alarm—and they are not automatically evidence that the tree must be removed.
Some fungi are simply decomposing mulch, buried wood, or other organic material. Others may be associated with decay affecting important roots, the root flare, trunk, or branches.
The visible mushroom is one piece of information.
Understanding its significance requires looking at what it is, where it is growing, what it is attached to, and how the rest of the tree is responding.
When in doubt, take clear photographs, avoid making conclusions from the mushroom alone, and consider a professional evaluation—especially when fungal growth is associated with structural parts of a large tree near people or property.
Related Reading
Signs Your Tree May Be in Trouble
When Should I Call an Arborist?
Should I Remove or Save My Tree?
Building Healthy Soil Around Mature Trees
HEALTHY SOIL. | STRONGER TREES. | LASTING LANDSCAPES.
Concerned about mushrooms, fungal growth, decay, or changes in one of your trees? UFT Tree Care Specialists provides objective, science-based tree diagnostics, consulting, and tree-risk evaluation throughout Northern Michigan.
ufttree.care • ben@ufttree.care • 231-409-0442
