Magnolias are magnificent trees with early spring flowers and glossy green leaves. If you see your magnolia leaves turning yellow and brown during the growing season, something is wrong. There are many reasons why your tree’s leaves are turning yellow, from natural to nutritional. You’ll have to do some troubleshooting to figure out what’s wrong. Read on for some tips on how to figure out why you have yellowing leaves on your magnolia.
Magnolias are treasured for their showy spring blooms and lush, glossy foliage. But if those large green leaves start yellowing, it signals trouble for your magnolia bush. Yellowing leaves on magnolia shrubs and trees rarely mean impending doom, but it does require some thoughtful troubleshooting to restore health. Let’s unpack the mysteries behind yellow magnolia bush leaves to get your shrub thriving again.
Understanding Magnolia Bush Needs
Magnolias include both shrubs and trees, ranging from small 6-foot shrubs to towering 80-foot trees. For this discussion we’ll focus on the causes of yellowing leaves on smaller magnolia shrubs and bushes.
Magnolia bushes thrive in zones 4-9 and prefer partly sunny spots with rich, acidic, moist soil. They perform best in locations that avoid harsh winds. Extreme dryness or sogginess should be avoided.
When Yellowing is Normal
It’s important to note that some yellowing of magnolia leaves is perfectly normal and nothing to worry about. Here are some examples:
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In fall, leaves naturally turn yellow as part of the seasonal transition to dormancy.
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As new leaves emerge in spring, older leaves may yellow and drop. This routine turnover is natural.
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A small percentage of yellowing leaves is expected as plants shed older leaves.
As long as new growth continues to appear and most leaves remain green and healthy, enjoy this natural process. But if extensive yellowing develops, read on.
Environmental Causes of Yellow Magnolia Leaves
If many leaves rapidly turn yellow, the problem likely lies in one of these environmental factors:
Improper Lighting
Insufficient sunlight leads to yellowing. Move the magnolia to a sunnier spot if possible.
Excessive Moisture
Wet, poorly draining soil causes roots to suffocate. Improve drainage through soil amendments
Under Watering
Parched soil from drought also yellows leaves. Apply deep watering when top few inches of soil become dry.
Damaging Weather
Frost, hail or high winds can damage leaves Protect plants with coverings as needed
Sunscald
Intense afternoon sun can scorch leaves yellow. Provide shade with nearby structures or plantings.
Soil Issues Causing Yellow Magnolia Foliage
Check these potential soil problems if you notice yellow magnolia leaves:
Improper pH
Magnolias need slightly acidic soil with a pH between 4.5-6. Use a soil test kit and amend pH if needed.
Nutrient Deficiencies
Lack of nitrogen, iron or other nutrients yellows leaves. Fertilize with a complete but acidic plant food.
Compacted Soil
If soil becomes too dense, roots suffocate. Loosen soil and mulch around magnolias.
Drainage Problems
Excess moisture leads to root rot. Improve drainage and avoid overwatering.
Diseases Causing Leaf Yellowing
These possible disease issues also lead to yellowing:
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Verticillium wilt – Causes yellowing in spots. Improve drainage.
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Bacterial leaf scorch – Marginal leaf browning spreads inward. Promote vigor with care.
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Root rot – Roots die back from excess moisture. Allow soil to dry between waterings.
Restoring Health to Yellowing Magnolias
Identify and remedy the underlying cause of yellowing, whether environmental, soil issues or disease. Here are some tips:
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Monitor soil moisture and water thoroughly only when the top few inches become dry.
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Test drainage by digging a small hole and filling with water. If water is still present after 12 hours, improve drainage.
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Fertilize in spring with an acidic fertilizer formulated for magnolias and camellias.
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Prune any dead branches or limbs, making cuts just above leaf nodes.
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Rake and remove fallen leaves and debris around plants.
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Protect magnolias from harsh winds and direct afternoon sun exposure.
With a little TLC and troubleshooting, you can get your magnolia bush back to its former vibrant glory. Don’t let a few yellow leaves cause undue concern. Just channel your inner detective to decipher the reasons behind the yellowing and remedy the cause.
Reasons for Magnolia Trees with Yellowing Leaves
If you see yellow magnolia leaves on the tree in your backyard, don’t panic. It might not be very serious. In fact, it might be natural. As part of their growth cycle, magnolias lose their old leaves all year long. The older leaves turn yellow and fall to the ground. Look carefully to determine whether new leaves are growing in to replace those yellow magnolia leaves. If so, you can relax. If not, continue troubleshooting. Another reason you might have a magnolia tree with yellowing leaves is soil acidity, or lack of it. Magnolias do best when the soil is neutral to slightly acidic. Buy a soil pH tester in the garden store. If your soil has a high pH and is alkaline, you might want to move the plant to a different spot or add something to the soil to make it more acidic. Poor irrigation is another reason you might have magnolia leaves turning yellow and brown. Too little water can cause drought stress, which results in yellowing leaves on magnolias. Too much water, or soil that doesn’t drain well, can drown the tree roots. This can also cause yellow magnolia leaves. Yellow magnolia leaves can also be a symptom of sunburn or insufficient light. Evaluate the tree’s placement and figure out if sunlight could be an issue. Generally, the trees prefer a growing site that gets good light. Sometimes an iron or other nutrient deficiency can result in yellowing leaves on magnolias. Get a thorough nutrient test done on your soil and figure out what the tree lacks. Buy and apply a fertilizer that offers the missing nutrient.