The Cause of Yellowing Tree Leaves – Iron Chlorosis

Date July 15, 2021


Author TreeNewal Staff

If fall has come early to your yard and you’re wondering why your trees are turning prematurely yellow, you are not alone. Chlorosis, or the Yellowing of Leaves, is a common occurrence in North Texas. Below is what you need to know about this issue in Dallas-Fort Worth and what you can do about it:

What is Chlorosis?

Chlorosis is a symptom, not a cause. It’s a broad term used to describe the premature yellowing of leaves on trees, shrubs, plants, and grass. It happens when Chlorophyll, the pigment responsible for making plants green, fails to develop. A lack of iron often causes it, but yellow leaves can be caused by other things, such as disease, lack of other essential nutrients or oxygen, injury from over-fertilization or harsh weather conditions, compact soil, or root rot. When the cause of the premature yellowing is iron deficiency, we call that Iron Chlorosis.

Why is Iron Chlorosis a common problem in North Texas?

Iron Chlorosis is often found in areas where the soil is highly alkaline. The high pH levels in the soil hold onto the iron and keep it from being absorbed by plants and trees. Without iron, a plant cannot create Chlorophyll, which is responsible for trapping light energy from the sun. Without it, a tree can’t perform photosynthesis. Certain plants and trees are more prone to Iron Chlorosis than others.

What should I look for?

When your tree or shrub is experiencing Chlorosis, the yellowing will first occur at the tips of the leaves and move inward. Often the veins will remain green, but as the deficiency worsens, or depending on the reason for the Chlorosis, sometimes even the veins will become yellow. Chlorosis typically starts on the newest growth first before eventually moving on to the older foliage.

How serious is Chlorosis? Can it kill trees?

Chlorosis in plants, shrubs, or trees signifies something is wrong, and you should take it seriously. If left unattended, your trees or shrubs could die. Also, if your tree is showing signs of Chlorosis, that means it is experiencing stress. When a tree is stressed, it is weak and vulnerable to attacks by pests or disease or damage by adverse weather conditions, so even if the Chlorosis doesn’t kill your tree, something else could. If you notice the leaves on your trees or shrubs turn prematurely yellow, you should contact a certified arborist immediately.

How can an ISA Certified Arborist help my trees or shrubs?

Because So many different things can cause chlorosis, it can be difficult for someone who doesn’t have in-depth knowledge about tree health and experience diagnosing the root cause of yellow leaves on plants, trees, or shrubs to assess what’s really going on skillfully. Beyond assessing the external health of the tree, an ISA Certified Arborist will be able to perform other tests. They can perform a soil test to check the condition of the soil, including the pH level and the levels of other essential nutrients. They can also check the tree’s roots to see if the issue might be that the tree cannot properly absorb the essential nutrients that are available because of damaged roots. Chlorosis can also be caused by soil that’s too compact, too dry, or too wet. An ISA Certified Arborist will tell if the source of the problem is a lack of oxygen in the soil or an issue of too much or too little water.

What options are available for treatment or prevention?

The treatment for the Chlorosis will depend on the reason for the problem. In the case of Iron Chlorosis, an ISA Certified Arborist might suggest adding iron supplements to the soil. However, the issue isn’t that the soil doesn’t contain iron; it’s that the tree cannot absorb the available iron. For example, if the pH levels in the soil are too high. In that case, the soil will need to be balanced to fit the needs of your tree, but you won’t be able to dump a bunch of iron into the soil and hope for the best. So, before you add iron to your soil, consult a certified arborist because incorrect treatment or over-fertilization could cause new issues. Root aeration might also be necessary, or a combination of root aeration and adding organic materials to the soil.

At TreeNewal, we have a special blend that we highly recommend to all our customers. TreeNewal developed it with three products proven to increase the growth and vitality of your trees and shrubs. Our blend uses the biochar brand VITAL Blend 5M, a plant-derived, organic soil enhancement product that charges the soil. This blend is beneficial for all trees and shrubs, but it’s beneficial for trees experiencing stress. The blend also includes humic and fulvic acids, high amounts of Active Carbon, and over 55 micronutrients, improving your tree’s metabolism, nutrient intake, and development. The biochar and humic acid are beneficial in remediating compacted soils.

A tree’s root hairs are responsible for its ability to soak up nutrients and water from the soil. Root hairs typically only live two to three weeks before they die off and are replaced by new growth. Stress can significantly reduce or even destroy root hair growth and development. This time-tested blend is a natural plant growth stimulator designed to boost your tree’s ability to absorb nutrients and develop a deeper, stronger root system, bark, and canopies. Our blend also includes MitoGrow, a rooting hormone, which stimulates and promotes root hair growth.

Does your tree have yellow leaves? TreeNewal’s ISA Certified Arborists can help!

If you’ve noticed a lot of yellow tree leaves in your yard and you suspect your trees or shrubs might be suffering from Iron deficiency Chlorosis or Chlorosis of any kind, you should reach out to a certified arborist tree service. At TreeNewal, we have multiple ISA Certified Arborists on staff, as well as a team of highly skilled tree care experts. We employ Tree Doctors Dallas homeowners trust, who care about tree health care in all stages of the tree’s life cycle. TreeNewal also offers expert tree care services</span>, such as pest and disease control, tree trimming, tree pruning, and root aeration. If your tree is past the point of saving, our tree surgeons can also handle professional tree care services such as tree removal or stump removal. They are trained and equipped to dispose of any infected trees safely, branches, stumps, or other debris. For more information, go to our website at To set up an appointment, call us at tel:(817) 592-6846.

To learn more about The Cause of Yellowing Tree Leaves – Iron Chlorosis, TX, call our Argyle and Southlake-based teams

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