Monster Tree Service of Rochester August Newsletter

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Beyond Green: Unveiling the Yellow Journey of Chlorosis

Welcome to the latest edition of our newsletter! In this issue, we turn our attention to a problem that affects tree species common to Rochester: Chlorosis. Chlorosis is a condition characterized by yellowing or whitening of leaves. It can be caused by various environmental stressors. But don’t stress about it yourself, we will explore the symptoms, causes, and effective treatments for chlorosis. So, let's dive in and help you discover how to identify, combat this issue, and promote a vibrant, green landscape!

leaves with chlorosis

A chlorotic Pin oak leaf. Notice the yellow tone of the leaf in contrast to the veins. 

Chlorosis is a condition in which leaves turn yellow due to a lack of chlorophyll, the green pigment that is essential for photosynthesis. The discoloration may vary from light yellow to pale green or even white, depending on the severity of the condition. In some cases, the veins of the leaves may retain their green color, creating a distinctive pattern. As chlorosis progresses, affected leaves may become stunted, exhibit necrotic spots, and drop prematurely. Monitoring leaf coloration and observing any changes can help in early detection and intervention. Easy examples you can see all around Rochester are Pin Oaks that have yellow canopies.

The symptoms of chlorosis can sometimes be confused with drought stress, as both can cause leaves to turn yellow and dry out. Click here to read our June newsletter which covers drought stress.

Here are some symptoms and ways to decipher if your tree is dealing with chlorosis or drought stress:

  • In chlorotic leaves, the yellowing typically begins on the older leaves and progresses to the younger leaves, while in drought-stressed leaves, the yellowing usually begins at the tips and progresses toward the base of the leaves.
  • Chlorotic leaves may feel normal in texture, while drought-stressed leaves often become wilted, crispy, or curled due to water loss.
picture of green leaves

Early signs of chlorosis on a sweet gum tree. Notice how these leaves do not yet have a yellow tone to them but are beginning to lighten allowing the veins to become more noticeable. 

Chlorosis in trees can arise from multiple causes, with nutrient deficiencies being the most common culprit. Lack of essential nutrients like iron, manganese, or nitrogen can disrupt chlorophyll production and result in yellowing leaves. Trees acquire these essential nutrients from the soil, so soil conditions play a vital role. Environmental stressors such as excessive moisture, poor drainage, compacted soil, and soil pH level can all contribute to chlorosis. Identifying the underlying cause is crucial in determining the appropriate treatment approach. There are two types of tests that can help narrow down the cause. A soil test can help an arborist understand the soil pH and the available nutrients in the soil. A foliar test will tell the arborist the nutrient content in the leaves but won't tell the arborist why the nutrients are deficient. Having soil and foliar analysis done together can help the arborist narrow down the main culprit so they can create a custom management plan.

Photosynthesis is the process by which trees transform sunlight, water, and carbon dioxide into oxygen and energy (sugar) that the tree needs to survive. Manganese and iron are two essential micronutrients for trees that play a key role in photosynthesis, as they are involved in the production of chlorophyll. Manganese helps trees use nitrogen more efficiently and helps trees withstand stress from high temperatures and drought. Iron plays a role in the formation of enzymes that are involved in the respiration, nitrogen fixation, and other important processes. If you have a chlorotic tree, it is not completing the photosynthesis process efficiently, which means it is not creating and storing enough energy for future growth, as well as for self-defense against pests & disease.

Before you run out and buy and apply some fertilizer, you want to make sure you consider the pH of the soil as well as age, health, and species of the tree. For example, in alkaline soil, a Pin Oak may have an iron deficiency, while an adjacent Maple, sharing the same soil, may be manganese deficient. Applying manganese and iron can help prevent chlorosis, but overapplying these nutrients can exacerbate different health conditions, as well as be toxic to the tree. Careful management of the soil pH and nutrient levels will help ensure that your trees and shrubs have the right environment for healthy development.

picture of tree being injected with fertilizer

Injecting the tree with a fertilizer that is enriched with iron and manganese, as well as supporting micronutrients, will allow for rapid distribution through the vascular system. 

Addressing chlorosis can require a multifaceted approach tailored to the specific cause. Nutrient deficiencies can often be rectified through soil injections or fertilization programs that address the issue. Treatments can also be applied through injections directly into the tree's xylem or by applying via a foliar spray. These nutrient solutions can be applied directly to the tree, allowing for quick absorption and utilization. However, it's important to note that foliar sprays and injections directly into the tree may not be a permanent solution for chlorosis. These application methods provide a temporary fix by directly supplying nutrients to the leaves. Addressing the underlying cause, such as a soil nutrient deficiency or pH imbalance, is critical for the long-term health of the tree. An easy step to take in chlorosis management is ensuring proper irrigation and managing environmental stressors.

Chlorosis is a common issue that can affect the health and appearance of your trees. By recognizing the symptoms, understanding the causes, and implementing the appropriate treatment, you can help your trees overcome chlorosis and thrive. Remember to consult with a certified arborist or tree care professional for guidance tailored to your specific tree species and environmental conditions. At Monster Tree Service of Rochester, we are here to support you in maintaining a vibrant and green landscape.

Find out more:

Schedule a consultation with a Monster Arborist

Cornell University: Micronutrient Chlorosis

USDA: Natural Resources and Concervation Services, Soil Sample Database

Monster Fun

photos of different tree barks

Which bark do you like best? 

A: Birch with its pink undertones and flakey strips

B: Sycamore with its camouflaged look

C: Scotch Pine because of the scaley plates that reveals a deep reddish-orange as it matures

D: Cherry, with its shiny, coppery-brown color and lenticles running horizontal along the bark

Monster in the Neighborhood

This spring our team was a part of preserving historic oaks and hickories at Cobbs Hill Park during a construction project with LG Evans Construction Inc. Our plant health care (PHC) team treated 14 trees throughout the site to protect them against the Two-Lined Chestnut Borer, a native borer that often attacks stressed or weakened trees. It was a rewarding experience to safeguard these majestic beings that are integral to our ecosystem and community. Remember, when we take care of nature, nature takes care of us. Let's keep our parks green and healthy.

map of Cobbs Hill Park with numbers on trees
worker injecting tree with treatment

Above right: Max, one of our Certified Applicators, injecting one of the selected oaks with a treatment to protect against Two-Lined Chestnut Borer.

Left bottom: a map of Cobbs Hill Park showing the number associated with each individual tree. Using this map our team identified the correct 14 trees to be treated.

Tree Highlight 

Pin Oak 

(Quercus palustris)

photo of Pin Oak tree

Also called: Swamp Oak, Swamp Spanish Oak, Water Oak

Lifespan: on average 100-200 years

ID features: 

Height- Typically 60-80 feet tall but can reach up to 100 feet! The spread can fall between 25-40 feet wide.

Pin Oak leaf

Leaves- Alternate, simple, 3 to 6 inches long, with five to seven lobes and deep u-shaped sinuses. Leaves are glossy dark green in summer, becoming russet, bronze or red in fall. 

Bark- shallowly ridged and becomes smooth gray with few isolated ridges.

Fruit/seed- The Pin Oak is not known for its flower: as it is brown and not showy. Fruit is a nut, half an inch long and wide, light brown, enclosed at the base in a thin cap.

Pin Oak tree bark
Pin Oak tree seeds

Fun facts: Pin Oaks are one of the fastest growing species of oak, averaging 12-15 feet in a 5-7 year period.

Pin Oaks are specially adapted to wetland environments. Their scientific name actually translates to "Oak of the marsh."

Pin Oaks have a central-leader giving it a more-slender appearance than other oaks. The Pin Oak has a unique branching pattern. The lowermost branches are angled sharply downward, the middle branches are more horizontal, and the upper branches are ascending.

Ask the Arborist


NYSDEC 3A Certified Applicator

cartoon photo of man

Q: Are there any tree species that are particularly susceptible to chlorosis?

A:  The most common trees I see with chlorosis are Pin Oaks. Other species in our area that are susceptible to chlorosis include Red Maple, Sweet Gum, River Birch, and Magnolia. Urban trees or new plantings in poor soil are most at risk.

Q: How long does it typically take for trees to recover from chlorosis once appropriate treatments have been applied?

A: It can sometimes take several treatments to correct chlorosis completely. Factors such as the severity of the condition, the specific cause of chlorosis, the tree species, and the effectiveness of the treatments applied will all play a role in the recovery timeline. You may notice an improvement in health within a few months once appropriate treatments have been applied. It may take several months to a year or more to see significant improvements in the tree's health.

Q: Are there any specific fertilizers or soil amendments that can be used to proactively prevent chlorosis in my trees?

A: Preventing chlorosis is always better than treating it. A lack of manganese and/or iron is the usual culprits for chlorosis. Incorporating organic matter and mulch into the soil can also help improve nutrient availability for trees. Having healthy, appropriately draining soil, can help your tree avoid chlorosis.