Friday, September 2, 2011

Treating Iron Deficiency

Have you ever had yellowing leaves with distinct green veins? Or have young new leaves that have strange formations as if they haven't fully developed at the branch tips? Or have discovered many leaves turning pale with a bit of a limp?  If your plant exhibits any of these signs, it probably has iron deficiency.  This year I had an issue with our live oak trees.  The top leaves of the trees weren't fully developed and I noticed yellowing on the bottom leaves with odd bright green veins.  So I did some research and here is what I found....
Pic taken from the AgriLife Extension in Texas

"Iron deficiency, called iron chlorosis, can be seen on the leaves of apple, peach, and citrus trees, and on gardenia, hibiscus, pyracantha and rose plants.  Although our desert soil contains plenty of iron, this nutrient is "locked up" in an insoluble form due to the soil's high alkalinity.  As a result, non-native plants such as those mentioned above struggle to absorb iron.  Native plants, on the other hand, seldom suffer iron chlorosis, as they have adapted to local soil conditions.  Iron also is not available for absorption if the soil is cold or wet.  The effects of iron chlorosis usually are visible in spring after months of cool temperatures, wet soil conditions, or during summer monsoon, when thundershowers are heavy.  As these seasonal variations disappear, the problem typically clears on its own.
The product above is $7.95 a quart.  There are other products like Capitol Brand Soil Sulfur which is made for Arizona Planting
Treatment is rather easy.  Examine the soil moisture and frequency with which the area is irrigated.  Make adjustments to allow the soil to dry out between waterings.  Irrigate deeply and as infrequently as possible, rather than sprinklings for brief periods daily.  Wait a month and observe any changes.  If adjusting the watering schedule doesn't improve the situation, the next step is to apply soil sulfur or a sulfur product.  Sulfur helps to slightly reduce soil alkalinity, making iron more available for uptake.  As a last resort, apply chelated iron. Chelates are chemical substances that hold metals such as iron in a form that plants can easily absorb over a long period.  Chelated iron may be added to the soil around trees and shrubs as a granular spread or applied as a foliar spray to the leaves of shrubs. Foliar applications work faster.  Use caution, however, when applying chelated iron, as it creates nasty stains on concrete and other surfaces.  Also don't spray it upward into trees because it will drift. " Written by Cathy Cromell.  Over the years, I have found her advice extremely helpful because it's specific to our desert climate. Today the live oaks are doing well.  More tomorrow....

1 comment:

  1. Glad you figured out the issue with your live oaks and and have had good results. We see this sometimes and for us it is usually because it has gotten to dry. I've treated some bushes in the past but now water good first and then check. Our soil is very alkaline too.


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