Brown Leaves on Dogwood: 11 Possible Causes & What To Do

Many homeowners enjoy Dogwood trees for their lovely appearance and easy upkeep. Nonetheless, these trees can encounter issues at times.

The browning of leaves is a relatively common issue that can occur for a variety of reasons.

In the following, we’ll discuss 11 possible causes of brown leaves on dogwood trees, how to identify each issue, and what you can do to help your tree recover.

Unfortunately, browning leaves is just one of the many issues that plague dogwood trees. Learn about the various conditions that signal something is wrong in my article, Common Dogwood Problems.

1. Extreme Heat or Drought

Extreme heat or drought can cause dogwood leaves to turn brown. During periods of high temperatures or prolonged dry conditions, the tree may struggle to get enough water to all its leaves.

As a result, the leaves may start to dry out and turn brown, especially around the edges.

How To Identify

Look for leaves that are brown around the edges and possibly curling inward. The browning may be more severe on the side of the tree that gets the most sun.

If the weather has been particularly hot or dry and the tree is not receiving regular watering, heat and dry soil are likely suspects.

What To Do

Water the tree deeply and slowly to ensure the water reaches the roots. Do this early in the morning or late in the evening to prevent evaporation.

Mulching around the base of the tree can help retain moisture. If the tree is young or newly planted, consider using a tree guard or shade cloth, like this one, to protect it from the sun.

2. Cold or Frost Damage

Cold or frost damage is another common cause of brown leaves on dogwood trees.

When temperatures drop significantly, the water inside the tree’s cells can freeze, causing damage to the cell walls. This can lead to browning and wilting of the leaves.

How To Identify

Frost damage often appears as a defined line or border on the leaf where the frost touched the foliage. The leaves may also appear water-soaked before they dry out and turn brown.

Damage is usually most severe on the outer and upper parts of the tree where frost has the easiest access.

What To Do

If frost damage is suspected, avoid pruning the affected areas immediately as this can cause further stress to the tree. Instead, wait until the last frost of the season has passed before removing damaged foliage.

To prevent future frost damage, consider using frost blankets or other protective measures when a freeze is expected.

3. Sunburn

Most people don’t know that trees can get sunburned. This is known as leaf scorch and usually happens when a tree that’s used to shade is suddenly exposed to a lot of direct sunlight.

The leaves can get scorched, leading to browning or whitening of the leaves.

How To Identify

Sunburned leaves often show a bleached or whitened appearance and may have a scorched look.

The damage usually appears on the side of the tree facing the sun and is often most severe on the youngest leaves, which are less equipped to handle intense light.

What To Do

If sunburn is the issue, consider installing a shade cloth to protect the tree from intense afternoon sun. Keep the tree watered as a well-hydrated tree is more capable of withstanding sun damage.

If the tree is newly planted, consider moving it to a location where it will receive more shade if possible.

4. Dogwood Anthracnose

Dogwood anthracnose is a fungal disease that can cause significant damage to dogwood trees. The disease is caused by the fungus Discula destructiva and is more prevalent in wet, cool weather.

How To Identify

Symptoms of dogwood anthracnose include tan or purple blotches on the leaves, often along the leaf veins.

These blotches may eventually turn brown. The disease can also cause twig dieback and large, sunken lesions on the trunk.

What To Do

If you suspect your dogwood has anthracnose, it’s important to act quickly. Prune and dispose of infected branches, and rake up and dispose of fallen leaves to prevent the spread of the fungus.

Fungicides can be effective, but they are best used as a preventative measure in the early spring. Consult with a local arborist or extension service for the best treatment options in your area.

5. Powdery Mildew

Powdery mildew is another fungal disease that can affect dogwood trees. It’s caused by a variety of different fungi and appears as a white, powdery substance on the leaves and stems of the tree.

How To Identify

Powdery mildew is relatively easy to identify due to its distinctive appearance. Look for a white or gray powdery substance on the leaves, stems, and buds of the tree.

The leaves may also become distorted or stunted, and in severe cases, they may turn brown and fall off the tree.

What To Do

To treat powdery mildew, prune and dispose of infected branches and leaves. Increase air circulation around the tree by thinning out branches. This can help prevent the fungus from spreading.

Fungicides can also be used to treat powdery mildew, but they are most effective when applied at the first sign of the disease.

6. Leaf Spot Diseases

Leaf spot diseases are caused by a variety of fungi and bacteria. These diseases cause spots on the leaves that can be a variety of colors, including brown.

How To Identify

Leaf spot diseases are characterized by spots on the leaves that may be brown, black, tan, or red.

The spots may be surrounded by a yellow halo. In severe cases, the leaves may turn entirely brown and fall off the tree.

What To Do

To manage leaf spot diseases, rake up and dispose of fallen leaves, and prune and dispose of infected branches.

Fungicides or bactericides may be used, depending on the cause of the disease.

As with other diseases, it’s best to consult with a local arborist or extension service for the best treatment options in your area.

7. Bacterial Leaf Scorch

Bacterial leaf scorch is a disease caused by the bacterium Xylella fastidiosa.

This bacterium infects the xylem vessels of the tree, which transport water from the roots to the leaves. As a result, the leaves become dehydrated and turn brown.

How To Identify

Bacterial leaf scorch often starts at the leaf margins and moves inward, causing a scorched appearance.

The browning often appears in a band around the leaf, separated from the green part of the leaf by a yellow or red halo.

The disease often starts on one branch and gradually spreads to the rest of the tree.

What To Do

There is currently no cure for bacterial leaf scorch, but you can manage the disease to prolong the life of the tree. Keep the tree watered sufficiently, and apply fertilizer to improve its overall health.

Prune and dispose of infected branches to slow the spread of the disease. In severe cases, it may be necessary to remove the entire tree to prevent the disease from spreading to other trees.

8. Fire Blight

Fire blight is a bacterial disease that can cause the leaves of dogwood trees to turn brown. The disease is caused by the bacterium Erwinia amylovora and is often spread by insects, rain, and wind.

How To Identify

Fire blight causes the leaves, branches, and flowers of the tree to appear as though they have been burned by fire, hence the name.

The affected parts of the tree will turn dark brown or black. The disease often causes a “shepherd’s crook” appearance, where the ends of branches curl over.

What To Do

To manage fire blight, prune and dispose of infected branches during the dormant season when the bacteria are not actively spreading.

Be sure to sterilize pruning tools between cuts to prevent spreading the disease. In some cases, antibacterial sprays may be effective.

9. Dogwood Borers

Dogwood borers are pests that can cause significant damage, including browning of the leaves.

The larvae of these insects bore into the trunk and branches of the tree, disrupting the flow of water and nutrients.

How To Identify

Look for holes in the trunk or branches of the tree, often accompanied by sawdust-like frass. The leaves may wilt, turn brown, and fall off the tree.

In severe infestations, the tree may have a general appearance of decline and may eventually die.

What To Do

To manage dogwood borers, prune and dispose of infested branches. Insecticides can be effective, but they must be applied when the adult borers are active and before they lay their eggs.

Consult with a local arborist or extension service for the best treatment options in your area.

10. Scale Insects

Scale insects are small pests that can cause the leaves of dogwood trees to turn brown. These insects feed on the sap of the tree, which can weaken the tree and cause the leaves to turn yellow and eventually brown.

How To Identify

Scale insects are often hard to spot because they do not resemble typical insects. They appear as small, immobile bumps on the leaves, stems, or branches of the tree.

They can be a variety of colors but are often brown or tan. The leaves of the tree may start to yellow and eventually turn brown if the infestation is severe.

What To Do

To manage scale insects, you can physically remove them from the tree by rubbing them off with a soft brush or cloth. Insecticidal soaps or oils can also be effective.

In severe cases, systemic insecticides may be necessary. As always, consult with a local arborist or extension service for the best treatment options for your particular situation.

11. Aphids

Aphids are small insects that can cause the leaves of dogwood trees to turn brown. They feed on the sap of the tree, which can cause the leaves to yellow and eventually brown.

Aphids also excrete a sticky substance called honeydew, which can lead to the growth of sooty mold on the leaves.

How To Identify

Aphids are small, soft-bodied insects that can be a variety of colors, including green, black, brown, white, and red. They are often found on the undersides of leaves.

In addition to the yellowing and browning of the leaves, you may also notice a sticky substance on the leaves or surrounding surfaces, which is the honeydew excreted by the aphids.

What To Do

To manage aphids, you can spray the tree with a strong stream of water to knock off the pests. Insecticidal soaps or oils can also be effective.

In severe cases, systemic insecticides may be necessary.

Closing Thoughts

Caring for a dogwood tree involves understanding the various factors that can lead to brown leaves.

From environmental stressors to diseases and pests, there are numerous potential causes for concern.

However, with careful observation and appropriate action, it’s possible to identify and address these issues to help your dogwood tree thrive.

Early detection and intervention are important. Regularly inspect your dogwood tree for any signs of distress and take action as soon as you notice anything unusual.

To learn more about what could go wrong with your dogwood tree, be sure to read these articles next: