14 Causes of Brown Leaves on Magnolia Tree & What To Do

If you have observed a magnolia tree’s leaves changing color to brown or falling off, you have found the appropriate source. Magnolias are stunning trees, however, they are also prone to vulnerabilities like any other living organism.

Browning of the leaves can be a gardener’s nightmare, but understanding the common causes is the first step to maintaining the health of your magnolia.

Because numerous factors can be to blame, it is essential to identify the cause behind the leaves turning brown and address it promptly. Ensuring proper water, nutrient balance, protection from pests, and other environmental factors can often mitigate or reverse the problem. 

Carefully read through the most common causes of brown leaves on magnolia trees found below to correctly pinpoint the problem and take steps to rectify the situation. 

Being aware of possible issues that can plague magnolia trees will help you prevent small problems from morphing into catastrophic ones. Educate yourself with my comprehensive guide, Magnolia Tree Diseases, Pests, and Problems.

Causes of Brown Leaves on Magnolia Tree (And Solutions)

Keep in mind that more than one of the following issues might be occurring. Take the time to properly inspect your tree for more clues, and compare what you find to the possible causes below. 

1. Lack of Water

When magnolia trees don’t receive enough water, especially during the summer months, their leaves may turn yellow before they turn brown and fall.

Drought stress is a common reason for magnolia leaves turning brown as the tree struggles to maintain its health.

As a gardener, you should monitor the soil around the magnolia, ensuring it remains consistently moist but not waterlogged.

Solution:

Water your magnolia tree deeply, allowing water to penetrate at least 6 inches into the soil. This ensures the entire root system gets a sufficient amount.

Mulch around the base of the tree can help retain moisture, reducing the frequency of watering. In prolonged drought conditions, you might need to water more often.

2. Nutrient Deficiency

A lack of nutrients in the soil can cause the leaves on your magnolia to turn yellow or display brown spots on the leaves.

A common cause is a deficiency in nitrogen, potassium, or phosphorus. A soil test can provide valuable insights into what your soil might be missing.

Solution:

Fertilize your magnolia tree with a balanced fertilizer that caters to its specific needs (this one is excellent).

For a newly planted magnolia, ensure it’s getting enough of the vital nutrients to establish a strong root system and vibrant foliage.

Always follow the fertilizer’s label directions and avoid overfertilizing, which can lead to other problems.

3. Frost Damage

Magnolias are sensitive to late frosts, especially when they bloom. Frost damage can cause the leaves to turn brown and droop, particularly on younger trees that haven’t fully established.

The damage is often more severe on the tree’s outer canopy where the frost directly contacts the foliage.

Solution:

If frost is forecasted, especially after a period of warm weather, cover your magnolia tree with a frost blanket (find them here) or old bedsheets to protect its delicate blooms and foliage.

Ensure the covering reaches the base of the tree to trap ground heat. For mature magnolia trees, prune back any frost-damaged branches to maintain the overall health of the tree.

4. Wind Desiccation

Harsh winds, particularly during winter, can cause magnolia leaves to turn brown as they dry out, a condition often referred to as windburn.

This issue is especially common in areas prone to strong winter winds or when the magnolia is planted in an exposed location.

Solution:

Protect your magnolia from harsh winds by planting it in a sheltered location or installing windbreaks.

During the colder months, regularly water the soil around the tree to ensure it doesn’t dry out.

Mulch around the base of the tree can also help in retaining soil moisture and reducing the impact of harsh winds.

5. Verticillium Wilt

Verticillium wilt is a fungal disease that affects the vascular system of magnolias. This disease can block the transport of water and nutrients, causing the leaves to turn brown and wilt.

Symptoms include yellowing of the leaves, followed by browning of the leaves and eventually, leaf drop. This disease can severely weaken a magnolia and, in severe cases, even cause its death.

Solution:

Maintaining the health of your magnolia is crucial in preventing verticillium wilt. Ensure it’s planted in well-drained soil as waterlogging can exacerbate the spread of this fungus.

If you suspect your tree is affected, prune away diseased branches, and dispose of them away from other plants.

In areas known for this fungal issue, consider planting resistant varieties. A master gardener or local gardening expert can provide recommendations.

6. Leaf Blight

Leaf blight is a fungal affliction causing spots on the leaves, which can eventually turn brown. As the disease progresses, the leaves may turn brown and fall prematurely.

This fungal disease thrives in humid conditions and can rapidly spread if not addressed.

Solution:

Remove and dispose of the affected leaves to prevent the spread of the fungus. Consider applying a fungicide like this one, but always follow the manufacturer’s instructions.

Improve air circulation around your magnolia tree by pruning overlapping branches, and avoid watering the foliage directly as damp leaves can encourage fungal growth.

7. Root Rot

Root rot, predominantly caused by overwatering, is a condition where the magnolia’s roots decay due to a combination of fungal infection and prolonged moisture.

Symptoms include yellowing of the leaves and a general decline in the tree’s vitality. Over time, the magnolia leaves may turn brown and drop off.

Solution:

Ensure your magnolia is planted in well-drained soil as stagnant water can lead to root rot. Reduce the frequency of watering if the soil remains soggy for extended periods.

If the root rot is advanced, consult with a gardening expert about potential treatments or the possibility of transplanting the tree to a better-draining location.

8. Phyllosticta Leaf Spot

Phyllosticta is a specific fungus that can cause small brown spots on the leaves of your magnolia tree.

As the disease progresses, these spots can coalesce, causing larger areas of discoloration and even premature leaf drop.

Solution:

Regularly inspect the leaves on your magnolia, especially after periods of prolonged rain or high humidity. Remove affected leaves, and apply a fungicide treatment if necessary.

Ensure proper spacing between your magnolia and other plants to improve air circulation, reducing the likelihood of fungal growth.

9. Leaf Scorch

Leaf scorch occurs when the magnolia tree absorbs water faster than it can be supplied from the roots.

This often happens during hot, windy days, leading to the edges of the magnolia leaves turning brown. Newly planted magnolias are more susceptible as their root systems aren’t fully established.

Solution:

Water your magnolia deeply and consistently, particularly during dry periods or before days of intense heat.

Mulch around the root zone can help the soil retain moisture and protect the tree’s roots from extreme temperatures.

If you have a newly planted magnolia, ensure it’s adequately watered until its root system matures.

10. Poor Soil Conditions

Magnolias prefer slightly acidic, well-draining soil. If the soil around your magnolia is either too alkaline or retains too much moisture, it can cause magnolia leaves to turn yellow and eventually brown.

Poor soil can also starve the tree of essential nutrients, weakening its overall health.

Solution:

Conduct a soil test to determine pH and nutrient levels. Amend the soil based on the results, adding organic matter if needed to improve its structure and drainage.

For soils that are too alkaline, elements like sulfur can be incorporated to increase acidity. Fertilize the magnolia with a balanced fertilizer, ensuring it receives all necessary nutrients.

11. Pest Infestation

Pests can be a significant concern for magnolia trees. Scale insects, whiteflies, spider mites, aphids, mealybugs, and black twig borers are all common pests that can cause magnolia leaves to turn brown.

The damage they cause varies from sucking the sap out of the leaves, causing them to droop and discolor, to introducing diseases.

Solution:

Regularly inspect the foliage and bark of your magnolia tree for signs of pest activity. Using insecticidal soap or horticultural oil can be effective against many pests, but always follow the manufacturer’s instructions.

Encouraging natural predators, like ladybugs, can also help keep pests in check. For severe infestations, consult a master gardener or gardening expert for specialized treatment recommendations.

12. Chemical Exposure

Accidental exposure to chemicals, including pesticides, weed killers, or even spilled gasoline, can cause the leaves on a magnolia tree to turn brown and fall.

These chemicals can burn or damage the leaves and, in some cases, affect the root system if they penetrate the soil around the base of the tree.

Solution:

Always use caution when applying chemicals in your garden, ensuring they don’t drift or spill onto your magnolia or its root zone.

If you suspect chemical exposure, flush the soil with plenty of water to dilute the potential contaminants. In the future, consider using barriers or protective sheets when applying any chemicals nearby.

13. Natural Leaf Aging

It’s a natural process for older leaves of a magnolia tree to turn yellow or brown as they age.

This is especially common during the fall months in deciduous magnolia varieties. You may notice older leaves turning brown and falling, making way for newer, younger ones.

Solution:

There’s no need for action in this case as it’s a part of the magnolia’s natural life cycle.

However, regular pruning can help in removing dead foliage and encouraging new growth, maintaining the health of your magnolia.

14. Normal Leaf Change for Deciduous Trees

Deciduous magnolias will lose their leaves in the fall as part of their natural cycle. During this period, it’s common for leaves to turn brown before they shed.

This doesn’t indicate a health problem but is instead a sign of the changing seasons.

Solution:

Simply rake and remove the fallen leaves to keep your garden tidy. This is an excellent opportunity to mulch around your magnolia tree, which can help protect its roots from the cold winter months ahead.

Magnolia Tree Care – Key Tips

Magnolia trees are renowned for their breathtaking blooms and majestic presence in gardens.

To ensure your magnolia remains healthy and thrives, consider the following essential care tips:

Watering Needs

While magnolias are relatively drought-tolerant mature trees, younger trees require consistent watering, especially in the summer months.

It’s crucial to water deeply rather than frequently, ensuring that the root system receives adequate moisture.

A good rule of thumb is to keep the soil moist, but not soggy, to prevent root rot.

Soil Quality

Magnolias flourish in slightly acidic, well-draining soil. Conduct a soil test every couple of years to monitor its pH and nutrient levels.

Amending the soil with organic matter can enhance its structure, and a balanced fertilizer can replenish essential nutrients.

Mulching

Applying mulch around the base of the tree can work wonders. Not only does it retain moisture and regulate soil temperature, but it also suppresses weeds that might compete for resources.

Ensure the mulch is spread in a 3- to 6-inch layer and is kept a few inches away from the tree’s trunk to prevent fungal growth.

Pruning

While magnolias don’t require extensive pruning, removing dead or diseased branches can promote better air circulation and overall tree health.

The best time to prune is shortly after the tree has finished blooming to avoid cutting off the next year’s buds.

Pest and Disease Monitoring

Regularly inspect your magnolia for signs of pests or diseases. Early detection can make treatment more effective.

If you’re unsure about a particular symptom, consult a master gardener or local nursery for advice.

Protection

In areas prone to harsh winds or frost, consider planting your magnolia in a sheltered location or using protective covers during particularly cold nights.

This can prevent frost damage and wind desiccation, ensuring the foliage remains vibrant.

Avoid Overcrowding

Magnolias need space for their expansive root systems.

If you’re planting more than one magnolia or placing other plants nearby, ensure there’s ample distance between them to avoid competition for water and nutrients.

Related Questions:

Will Brown Magnolia Leaves Turn Green Again?

Once a magnolia leaf turns brown, it won’t turn green again, but addressing the underlying issue can prevent further browning in still-green leaves.

Should I Cut Brown Leaves Off Magnolia?

Pruning brown leaves can help improve the overall health of the tree and its appearance. Always use sanitized pruning tools.

Final Thoughts About Magnolia Leaves Turning Brown

Magnolia trees, with their grand blooms and robust presence, can sometimes face challenges.

By understanding and addressing common reasons for their leaves turning brown, you can ensure their longevity and beauty. Remember that the right care can make a significant difference.

Ready to learn more about magnolia tree problems and treatments? Be sure to explore these guides next:

• Leaf Curl on Magnolia Tree: 9 Common Causes & What To Do
• Ants on Magnolia Tree: Why, Implications & How To Treat