En EspaŅol

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
3 ratings

Thursday - August 04, 2011

From: Kyle, TX
Region: Southwest
Topic: Compost and Mulch, Diseases and Disorders, Trees
Title: Chlorosis in sycamore in Kyle TX
Answered by: Barbara Medford

QUESTION:

I'm trying to assist an elderly neighbor of mine with a plant issue. We have designated street trees in this community, our street being a Sycamore. The previous foreman out here called it a Mexican Sycamore. My neighbor's is almost completely yellow and has been this way for months. The bark looks good. There are visible new buds/growth along the limbs. However, most of the leaves are yellow, many with spotting throughout that looks rust colored. I've done some research on the internet and the issues that come up with more frequency are a deficiency in either iron or nitrogen. If this is the case, I was considering a two-staged response consisting of a liquid fertilizer for initial treatment, along with something like Miracle Gro tree spikes for long-term. Any comments/input that you might have would be appreciated.

ANSWER:

We found an article on Chlorosis in Trees and Shrubs from Washington State University from which we extracted this paragraph that sounds like the symptoms you are reporting:

"Plants with iron chlorosis first turn yellow-green to yellow between the veins, with the veins remaining a darker green. With more severe chorosis the leaves  become pale yellow and develop brown spots between the main veins. Leaf margins may also turn brown with the leaves later drying up and falling off. Tree growth slows to a stop and dieback of branches can occur when iron chlorosis is extremely severe."

You have found good information in your research; however, we feel that the biggest problem causing chlorosis, especially in trees, is our highly alkaline soil in Central Texas. Here is a previous Mr. Smarty Plants question and answer on that particular problem. The previous question is concerning a different woody plant, but the principles are the same. Our take on all this is that not only is our soil alkaline, but has a lot of clay, which severely limits proper drainage around the roots.

This USDA Plant Profile Map shows that Platanus occidentalis (American sycamore) is native to this area, so you would expect it to be somewhat tolerant of our soils. In the Growing Conditions on this tree (please read all of our webpage by following the above plant link) this comment appears on preferred soil: "Soil Description: Moist, sandy loams or silty clays."  While your ideas on nutrient supplements are good, the basic problems of alkalinity and clay soil, which drains very poorly, still remain. Adding amendments to the soil when the tree roots are unable to access them is not going to be worth the time and expense.

Here is one more article on Iron Chlorosis, which discusses some treatments that are pretty extreme, and probably can't be attempted by a home gardener. One thing we observed from our research is that the sycamore is a moist soil tree, most often occurring naturally in riverbeds and forest areas. With our extreme heat and drought this year, all trees are somewhat stressed. We recommend you begin with attempting to get more moisture to the roots, sprinkling out some distance from the trunk, as the roots are farther out in the soil than the dripline of the tree. Second, try mulching the roots with a good-quality shredded bark mulch. This will help keep moisture in, cool the roots and, as it decomposes, improve the texture of the soil in terms of better drainage.

It is very difficult to address poor drainage in a mature tree, so taking some short-term measures to help the tree survive is advisable. Then, hopefully gradual additions of compost and/or mulch to improve drainage will improve the life expectancy of the tree. If you wish to try injecting some iron and manganese in the soil this may help in the long run as the soil improves and allows the roots to access those elements.

 

 

From the Image Gallery


American sycamore
Platanus occidentalis

More Diseases and Disorders Questions

Problems with non-native zucchini in Muskogee, OK
July 23, 2011 - In the awful heat of this summer I am still getting zucchini to produce. But, once it grows about 3 inches, it gets yellow on the ends and dies. Am I watering it too much? (I have sprayed for bugs ...
view the full question and answer

Yellow bands around edges of leaves in Whitney TX
July 20, 2009 - How can you tell whether esperanzas are getting too much water or not enough - ours have a small yellow band around the edges of the leaves - crape myrtles - same question
view the full question and answer

Yellowing leaves on yaupon in Ft. Worth
April 23, 2009 - I planted a Pride of Houston Yaupon Holly in January in full sun. It is blooming little white flowers right now for spring, but a lot of leaves are turning yellow. Do you know what is causing this? ...
view the full question and answer

Spots on persimmon tree leaves from Dripping Springs TX
July 10, 2013 - We are in rural Hays County Texas off Hamilton Pool Rd Texas. Large persimmon trees are turning yellow, blackish spots on underside of leaves. What do we do?
view the full question and answer

Recovery from transplant shock for bougainvillea
July 12, 2007 - I live outside of Phoenix. I just bought a bougainvillea in a large pot. It was doing nicely until I brought it home. I placed it in a sunny spot in my front yard inside of a large volcanic rock that ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center