9 Reasons Your Magnolia Tree Has Yellow Leaves

Magnolia trees are very hardy for flowering trees, and in quite a wide range of climate zones. With varieties that can live in zones 3-12, they are a very wide-ranging family of plants. A mature magnolia can be nearly indestructible, healing from all kinds of damage caused by pests and diseases that kill more delicate trees.

So, when your beloved magnolia starts looking faded and leaves begin to yellow, it can be a cause for concern. There are a number of reasons that a magnolia’s leaves would change color. Some of them are a natural cycle in the life of the tree, while others are an indication that there is a problem.

Whatever the issue is, large or small, it’s always good to know what is going on. Addressing it early will allow you to correct the issue before it leads to more damage. It will also allow the tree the ability to begin repairing itself. Let’s talk about some of the predominant reasons that magnolia leaves turn yellow and see if we can’t help nurse that tree back to its original glory.

Seasonal Change

Deciduous magnolias naturally change color in the fall when the weather begins to cool. This color change is generally in the yellow/gold/bronze family. Leaves that are turning these colors are just reaching the end of their life, and the tree is going dormant.

The leaves will turn color, and fall, and in the spring, the tree will grow new, healthy, green leaves. When you see this starting to happen, there’s really no major cause for concern.

The Fix

There’s nothing to fix in this event. While you may be concerned that the color change could be due to another issue, a good way to make this determination is to look for buds.

If your magnolia is losing leaves, but has formed buds, and the buds look healthy, your tree should be just fine. If the buds are also looking damaged, you may have a more serious issue.

Natural Leaf Dropping

In evergreen magnolias, trees periodically drop leaves as the leaves reach the end of their lifespan and new growth is created. It is natural for leaves to turn yellow as the tree redirects nutrients to that newer growth.

This is also a common occurrence as the tree prepares to bloom. Nutrients are redirected to the growing buds and some of the older leaves will naturally lose their place.

The Fix

Maintaining the right balance of nutrients and water will help keep your magnolia looking its best year-round. Fertilizing during the growing and blooming season will maintain the maximum amount of old and new growth.

Don’t panic if there is a leaf drop in the middle of the summer, just be on the lookout for buds!

Soil Alkalinity

Poor soil quality is the number one factor in nutrient deficiency. Magnolias like soil with a decent amount of acidity. Soil that is too alkaline will inhibit the tree’s uptake of minerals such as zinc, iron, and manganese.

Acidic soil breaks down the nutrients that magnolias need to the extent that they are able to best absorb and utilize.

The Fix

Most soil is not deficient in these minerals, but the tree can’t absorb them without the proper level of acidity to break them down. You can solve this problem by acidifying the soil. Adding organic matter to the soil is the most natural and long-term solution.

Pine mulch and needles work well, as well as fallen leaves from neighboring trees. Commercially available soil acidifiers also serve this purpose.

Under Fertilization

If you know that your soil is adequately acidic, and your leaves are still looking undernourished, it may be time for some fertilizer.

Magnolias don’t need to be fertilized often, but they do benefit from some added nutrients, particularly during times of extreme water fluctuation. If there has been more rain than usual, or not enough, your magnolia could be having difficulty absorbing enough nutrients from the soil.

The Fix

A nitrogen heavy fertilizer, three times per year, will keep your magnolia flush with the extra nutrients that keep it looking green and healthy. Simply spread the fertilizer on the ground around the trunk and if there is no rain expected, water it in deeply.

Underwatering

Those leaves are the first place that your magnolia will let you know that it is thirsty. If the leaves are looking yellow and droopy, there’s a good chance your tree needs a long drink. The younger the tree, the more common you will encounter this issue. Mature magnolias are quite drought tolerant.

Young magnolias need regular watering to help them establish roots. A shallow root system is a weak root system, so establishing roots is important.

The Fix

Planting during the rainy season is a great way to help this along naturally. If you aren’t getting regular enough rain to keep the ground moist, watering twice a week is good for newly planted magnolias.

Place a hose at the base of the tree and allow it to run for 10-15 minutes, this should give the ground a good soaking.

Overwatering

Apart from the “Green Shadow” and maybe one or two other M. virginiana varieties, magnolias do not like soggy roots. Soggy roots open the tree up to fungal infections, which grouped together constitute root rot.

When root rot occurs, the first signs of a fungal infection will generally be yellowing leaves. The leaves are the farthest part of the tree from the roots, and when the roots are damaged or not able to take in enough nutrients, the leaves are the first part of the tree to suffer.

The Fix

Avoid planting magnolias in areas with poor drainage. Magnolias are versatile in the types of soil they tolerate, as long as they have good drainage.

If your magnolia is already established in a space that stays wet, avoid any additional watering. Make sure to fertilize adequately so that there are enough of those nutrients to go around. Lots of water means the nutrients in soil are diluted, which can make it difficult for a plant to absorb enough.

Late or Early Frosts

This Issue applies mainly to deciduous varieties and is the number one issue that affects the flowers and new foliage of spring blooming varieties.

When growing magnolias in colder climate zones (think zone 7 and north) there is always the possibility of a late frost. Many varieties bloom in late winter and early spring. They will sprout leaves around the same time, or very shortly thereafter.

If a magnolia blooms and leaves out before the last frost, you are likely to lose at least a portion of the flowers and foliage to cold damage.

Fortunately, there are hybrid varieties that have been bred specifically to combat this issue by blooming 2-4 weeks later than their parent plants. Planting a variety that has this characteristic is a great way to solve this issue.

The Fix

If you have your heart set on a magnolia that hasn’t been bred for cold hardiness, it’s still possible to take some preventive measures.

Avoid planting with southern exposure, as southern exposure will encourage a tree out of dormancy earlier, by several weeks in some cases. Giving your magnolia some protection from cold winds is also a great idea if you want to avoid cold damage.

Excessive Heat and Sun Exposure

Just as cold weather can damage a magnolia, so too, can excessive heat and drought. If your magnolia is looking dry and crunchy, with yellow, brown, and falling leaves, it may be getting too much sun or heat. Magnolias are sun lovers in general, but too much sun can cause leaves and flowers to wilt before their time.

Magnolias will show that they are getting too much sun and heat by getting a sunburn. The leaves will look faded and bleached rather than their usual bright to deep green color.

The Fix

Your first thought might be to move your magnolia to a place with less exposure. While this may be possible if your tree is young, with a mature tree, this is somewhat impractical. A good solution would be to plant larger trees strategically to give your magnolia a little respite.

 You can also increase watering during the hotter months if there is little rain. Put down some mulch to help hold in the moisture and protect the roots. Magnolias have quite shallow and wide-reaching root systems.

Not Enough Sunlight

This issue is one that affects flowering more than yellowing of leaves. But if the lack of light is extreme enough, you will have a decrease in the vigor of leaves as well as a lack of flowering.

While some magnolia trees are partial-shade friendly, most varieties of Magnolia like a lot of sun. They typically are grouped with plants that require full sun (6 or more hours per day). An established magnolia will tolerate most conditions to some extent, but a younger magnolia needs sunlight to grow and thrive.

If your magnolia’s leaves are looking paler than they ought to, and the tree is not producing flowers during its typical blooming season, it may need more sunlight.

The Fix

Short of moving the tree to a sunnier location, you may be able to trim back any larger tree limbs that are inhibiting sun exposure. In general, plant your magnolia in a spot that gets plenty of sunlight. This will help encourage it to produce the greatest number and quality of flowers.