iron chlorosis

Sick Yellow Trees in Utah: Iron Chlorosis

Temperatures in August haven’t turned much cooler, yet some trees may look like fall is already here. If your tree’s leaves are turning yellow or falling off prematurely, your tree might have iron chlorosis.

severe iron chlorosis
Severe Iron Chlorosis

Iron Chlorosis: Defined

Iron chlorosis is a deficiency of the nutrient iron in trees—it’s kind of like having an anemic tree. This problem is common in Utah and develops when trees struggle to bring in essential nutrients from the soil.

Soils in Utah have a good level of iron. So, why do some tree roots struggle to soak it up? The answer is simple: Utah’s clay-like soil is alkaline (a pH level of 7 or higher), so chemical reactions in the soil cause the iron to harden, making it inaccessible to tree roots. In order to thrive, trees need their iron in a form that is easy to absorb.

Identifying Iron Chlorosis

Iron chlorosis is especially detrimental to Autumn Fantasy and Autumn Blaze Maple trees. Early stages of iron chlorosis turn tree leaves light green with visible, dark green veins. This is evidence of a lack of chlorophyll, the green pigment essential in photosynthesis.

Iron Chlorosis in a Maple Tree
Early Stage Iron Chlorosis

Eventually, the leaves will weaken and turn yellow. In their weakened state, leaves may scorch in the summer heat, which curls and browns the edges. If the leaves remain deprived of chlorophyll, they eventually die and fall off the tree. Without treatment, the problem will progress to the point where the tree begins to lose limbs, and eventually, the entire plant may die.

Often, trees affected by iron chlorosis still have green, healthy-looking sections along with the defoliated parts. Some trees in the early stages of iron chlorosis have evenly dispersed, yellow-green leaves with brown, shriveled leaf edges.

Trees in parking strips are especially susceptible to iron deficiencies because of their position between the sidewalk and the road. The roots have to compete with the heat radiating from the paved surfaces and the general lack of nutrients beneath roads.

Treating Iron Chlorosis

iron chlorosis before and after stewarts treatments
Iron Chlorosis Before and After Treatment

Fortunately, iron chlorosis is treatable. Trees develop iron chlorosis because they are not receiving iron from the soil, so in the early stages of iron chlorosis, soil treatments are recommended. If the tree is in the late stages of iron chlorosis, it should be treated with injections of iron directly into the tree trunk.

Keep in mind that most iron fertilizers in Utah’s stores won’t fix the problem. In this case, more iron just means more solid food in the soil that your plants can’t absorb.  This type of iron may be beneficial for plants in other states, but not in Utah.

Instead of surface-level iron fertilizers, Stewart’s uses a specific type of “smart iron” called chelated iron that is specially formulated to work in high PH soil without solidifying.  Stewart’s deep root fertilizer treatments saturate the soil around your plants with chelated iron and other nutrients, providing an easy food source for your plants to absorb. Spring and fall treatments provide a full year of nutrition for most plants.

For plants with severe iron chlorosis, deep root fertilizer treatments will not be enough to help the tree recover. In these cases, we bypass the root system altogether and inject iron directly into the trunk. We may also do this for trees that are located in parking strips and other areas where the roots are inaccessible.

Iron chlorosis treatments are difficult to do properly; they require careful training and a practiced hand, so only trust qualified experts like Stewart’s arborists to do them properly.


Text or call our office at 801-226-2261 if you think your tree has an iron problem; one of our certified arborists can evaluate your plants, make recommendations for treatment, and give you a free service quote.