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Friday - May 25, 2012

From: Allen, TX
Region: Southwest
Topic: Diseases and Disorders, Planting, Trees
Title: Yellow in pin oak leaves from Allen TX
Answered by: Barbara Medford


I have two pin oaks and one is completely yellow - a sign of iron deficiency and the other is starting to turn completely yellow as well. I've a proposal for iron deficiency but it is quite expensive. The company called it a "Verdur" treatment and said it will help the trees maintain their health for the next 3 - 5 years. What are your thoughts? Should I remove the trees and plant something else? These trees are approximately 10 years old. Thank you.


We always start with where a plant belongs and is it growing there. The first thing we do is look at the USDA Plant Profile for that plant. This map shows states in green where Quercus palustris (Pin oak) grows natively. You will note that Texas is white all over, but your location in Allen, TX is near the Oklahoma and Arkansas borders. Here is the map with counties in green for this plant for Arkansas. Most of the green counties are to the northeast of that state. Same plant, this map for Oklahoma shows a tiny blob of green in Love County on the south central state line with Texas, near Collin County, but the bulk of the occurences are, again, northeast Oklahoma. So, what does this tell us? Well, first it means there could be incompatibility in soils with what the Pin Oak requires.

According to our webpage on Quercus palustris (Pin oak) (follow the link to read the page):

"Conditions Comments: One of the faster growing oaks. Tolerates wet feet. Intolerant of alkaline soils. Susceptible to iron chlorosis which causes yellow coloration in the leaves through the summer months and can eventually kill the tree."

Highly alkaline soil is always suspect in the case of chlorosis. From the University of Illinois Extension here is a very good explanatory article about chlorosis. Also, here is an article on Iron Chlorosis in oaks from Arborilogical Services. Here is an extract from that article:

"High Volume Injection is another method of providing supplemental iron.  A material containing chelated iron can be  injected directly into the tree’s root flare.  Arborilogical Services has been treating trees with Iron Deficiency with the chelated iron product, Verdur®, for a number of years.  It is consistently meeting our expectations.  Verdur should be applied once every three years while the tree is in its winter dormancy.  Verdur can be applied exclusively, or in combination with soil amendments.

In some situations, it may be better to remove the tree and replace it with a species that is better adapted to the existing soil’s pH.  Your Certified Arborist can provide you with a list of recommended trees for your area.  The decision to replace a tree should be based on the homeowner’s opinion of how important the tree is to them, the cost of treatment for the tree’s life, and the tree’s overall health." (emphasis ours)

Here is an article on Verdur with illustrations, etc. We can see why it would be expensive. You are the only one that can make the decision, especially since only about 3 years of health is even mentioned. You might consider that ten-year old trees that are never going to be compatible with the soil they are in should probably be replaced by trees that like alkaline soils.

From our Native Plant Database, here are some trees that are native to Collin County and like alkaline soil. Do not purchase or plant trees until November to January. We recommend all woody plants be planted when they are dormant. CAUTION: Be sure that whatever trees you select for replacement, if you go that route, are able to live in alkaline soils. And, since we found a great many trees that our webpages say need acidic soils, but we know they are growing in alkaline soils, be sure the holes for whatever tree you select are amended with compost, and prepared for good drainage. See our Step-by-Step Article How to Plant a Tree.

Trees native in or near Collin County:

Aesculus glabra var. arguta (Ohio buckeye)

Cercis canadensis (Eastern redbud)

Cornus drummondii (Roughleaf dogwood)

Diospyros texana (Texas persimmon)

Ilex vomitoria (Yaupon)

Maclura pomifera (Osage orange)

Platanus occidentalis (American sycamore)

Quercus alba (White oak)

Quercus stellata (Post oak)


From the Image Gallery

Ohio buckeye
Aesculus glabra var. arguta

Eastern redbud
Cercis canadensis

Roughleaf dogwood
Cornus drummondii

Texas persimmon
Diospyros texana

Ilex vomitoria

Osage orange
Maclura pomifera

American sycamore
Platanus occidentalis

White oak
Quercus alba

Post oak
Quercus stellata

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