Tree Bark Peeling: Normal vs Problem by Species

Peeling or flaking bark generates more concerned phone calls to cooperative extension offices than almost any other tree question, per Penn State Extension. In the majority of cases, the bark is peeling normally as part of the tree's natural growth process. In a smaller but important subset of.

—- title: "Tree Bark Peeling: Normal vs Problem by Species" slug: tree-bark-peeling hub: care category: "Tree Care" description: "Bark peeling on trees is normal for dozens of common landscape species and a serious symptom in others. This guide identifies normal exfoliating bark by species and explains the disease and damage patterns that require attention." date: 2026-06-10 updated: 2026-06-10 author: "Thomas A." reading_time: 8 —-

Peeling or flaking bark generates more concerned phone calls to cooperative extension offices than almost any other tree question, per Penn State Extension. In the majority of cases, the bark is peeling normally as part of the tree's natural growth process. In a smaller but important subset of cases, peeling bark is a symptom of disease, pest damage, or abiotic injury requiring attention.

The diagnostic key is knowing which species naturally exfoliates, and for those that don't, recognizing the distinguishing features of problem peeling.

—-

Trees That Naturally Exfoliate (Normal Peeling)

Per Missouri Botanical Garden and Penn State Extension, the following species shed bark naturally as their diameter increases:

Sycamore (Platanus occidentalis) and London Planetree (P. × acerifolia)

Sycamore produces some of the most dramatic exfoliating bark in the North American landscape. The outer bark peels in large irregular patches, exposing a mottled surface of white, gray, green, and tan underlayers. Per Missouri Botanical Garden, this is entirely normal and is considered ornamentally distinctive. The bark peels because the outer layer cannot expand with the tree's growth and breaks off in plates.

River Birch (Betula nigra) and Paper Birch (Betula papyrifera)

Per NC State Extension, river birch naturally exfoliates in thin, paper-like sheets that curl away from the trunk, revealing cinnamon to salmon-colored inner bark. This is a defining ornamental feature. Peeling increases as the tree matures; on very young trees (first 2—3 years), peeling is minimal.

Paper birch (B. papyrifera) peels in white sheets. Per Penn State Extension, do not peel birch bark manually — this opens the tree to disease and removes the protective outer layer. The tree sheds what it needs to shed.

Crape Myrtle (Lagerstroemia indica)

Per NC State Extension, crape myrtle exfoliates in thin smooth strips on mature trunks, exposing a mottled tan-gray-pink under-bark. The peeling is year-round and increases with age. This is a normal, valued ornamental feature. Crape myrtle with healthy bark peeling and no lesions or sunken areas is not diseased.

Paperbark Maple (Acer griseum)

Paperbark maple (Acer griseum) is specifically cultivated for its peeling, cinnamon-colored bark. Per Missouri Botanical Garden, USDA zones 4—8; the exfoliating bark is the defining ornamental feature and occurs across the trunk and larger branches.

Shagbark Hickory (Carya ovata)

Per NC State Extension, shagbark hickory develops long, loose, shaggy strips of gray bark that peel from both ends but remain attached in the middle. This is normal and increases with age — old specimens can have spectacular shaggy trunks. No intervention needed.

Stewartia (Stewartia spp.)

Stewartia (S. pseudocamellia and others) develops a multi-colored exfoliating bark — gray, orange, and cream — as it matures. Per Missouri Botanical Garden, it is among the finest four-season ornamental trees, and the peeling bark is a primary winter ornament.

—-

When Bark Peeling Is a Problem

Per Penn State Extension, bark peeling on species that don't naturally exfoliate — or bark peeling accompanied by other symptoms — indicates a problem.

Cankers

Per NC State Extension, fungal and bacterial cankers kill bark patches and cause peeling or cracking of the dead tissue. Characteristics:

• Sunken, discolored (dark brown to black) patches of bark
• Distinct margin between healthy and dead bark
• Dead bark cracks and falls away over time
• Often surrounded by callus tissue the tree is generating to seal the wound

Common canker diseases: Cytospora canker in stone fruits, pines, and spruce (Cytospora spp.); Nectria canker in hardwoods (Nectria spp.); Botryosphaeria canker in many ornamentals.

Per Penn State Extension: Cankers are most common in stressed trees — drought-stressed, winter-injured, or mechanically damaged. Maintaining tree health through proper irrigation, mulching of the root zone, and avoiding trunk wounds (mower damage, weed trimmer wounds) reduces susceptibility.

Borer Damage

Per Cornell Cooperative Extension, several borers cause peeling or bark lifting as their tunneling kills bark tissue from underneath:

• **Emerald ash borer (Agrilus planipennis):** Serpentine galleries visible under bark that lifts or peels; D-shaped exit holes; woodpecker damage to infested areas. Kills virtually all untreated ash (Fraxinus spp.) within 2—5 years of infestation. Per Penn State Extension, treatment with systemic insecticides (emamectin benzoate, dinotefuran, imidacloprid) is effective when started before greater than 30% canopy loss.
• **Bronze birch borer (Agrilus anxius):** Similar D-shaped exit holes in birch; associated with stressed or drought-weakened trees
• **Flatheaded appletree borer (Chrysobothris femorata):** Young shade trees; irregular bark lifting with visible galleries; sap staining

Sunscald / Southwest Injury

Per Penn State Extension, winter sunscald (southwest injury) occurs when bark on the south or southwest-facing side of a trunk is heated by winter sun, then rapidly refreezes as the sun sets. This causes a long, vertical strip of dead bark on young trees, particularly fruit trees and thin-barked species (maples, lindens).

Appearance: A sunken, elongated vertical crack or dead bark strip on the south or southwest side of the trunk, most visible in late winter or spring. The dead bark peels or cracks away from the tree.

Prevention: Per Cornell Cooperative Extension, wrap the trunks of young trees (under 4 inches diameter) with white tree wrap or light-colored burlap from November through March, in the first 3—4 years after planting. White plastic spiral guards also work.

Frost Cracks

Per NC State Extension, frost cracks are vertical splits in bark and wood caused by rapid temperature drops. They can close and reopen seasonally for years. They are most common on large-diameter hardwoods (oak, maple, beech) on the north-facing side of the trunk. The cracks may look alarming but rarely threaten tree survival.

Differentiating from borer damage: Frost cracks are clean, vertical splits; borer damage shows galleries, frass, or exit holes.

—-

Gummy Sap Associated with Peeling

Per Clemson HGIC, gummosis — amber, sticky sap oozing from bark — associated with peeling bark on stone fruits (peach, cherry, plum) indicates one of three causes:

1. Cytospora canker: Fungal canker; dead bark; associated sap flow
2. **Peach tree borers (Synanthedon exitiosa):** Gummy sap at the base of the trunk; larvae tunneling inside
3. **Bacterial canker (Pseudomonas):** Oozing sap from bark lesions in spring; most common on cherry

—-

Summary: Normal vs Problem

—-

FAQ

My maple is peeling bark in strips that pull away easily. Is it sick? Per Penn State Extension, check whether the exposed wood beneath is healthy (cream-colored) or discolored (brown/black). If healthy and the rest of the tree grows well, this may be natural exfoliation on a silver maple or a weather-related bark check. If the exposed wood is discolored and the area is sunken, submit a sample to your county extension service for diagnosis.

Should I remove peeling bark from my trees? Per Cornell Cooperative Extension, do not peel or remove bark from naturally exfoliating trees — this removes protective tissue. For dead bark over a canker, the tree naturally sheds dead bark; you can remove loose dead bark to check for borer galleries underneath, but do not cut into live tissue around cankers.

My crape myrtle is peeling and the peeled areas look slightly pinkish. Is that normal? Yes. Per NC State Extension, the pink to salmon underlayer exposed by crape myrtle exfoliation is normal and is part of what makes the bark attractive in winter.

—-

Sources

1. Penn State Extension &mdash; <a href="https://extension.psu.edu/tree-bark">Tree Bark Problems</a>
2. Missouri Botanical Garden &mdash; <a href="https://www.missouribotanicalgarden.org/PlantFinder/">Plant Finder</a>
3. NC State Extension &mdash; <a href="https://plants.ces.ncsu.edu">Tree Species Profiles</a>
4. Cornell Cooperative Extension &mdash; <a href="https://cce.cornell.edu">Tree Bark Disorders</a>
5. Penn State Extension &mdash; <a href="https://extension.psu.edu/canker-diseases">Canker Diseases of Trees</a>
6. Clemson HGIC &mdash; <a href="https://hgic.clemson.edu/factsheet/gummosis/">Gummosis</a>
7. Penn State Extension &mdash; <a href="https://extension.psu.edu/sunscald">Sunscald</a>