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
Not Yet Rated

Friday - September 03, 2010

From: Austin, TX
Region: Southwest
Topic: Trees
Title: Pecan Trees in Austin, TX prematurely losing their leaves.
Answered by: Marilyn Kircus

QUESTION:

Why are the leaves on the pecan trees falling so early this year.

ANSWER:

I suspect that you are seeing cultivars of pecans which may be much less resistant to stress and diseases, although “native” trees are possibly also being stressed to the point of losing their leaves.  “Native” pecans are recommended for yard trees because of their greater natural resistance to stress and disease and because they don’t kill themselves by producing more nuts than they can actually support.  “Native” in this context refers to trees that occur naturally and are not cultivated varieties. 

Second, I’ve seen lots of pecan trees that lose leaves and also limbs when they don’t get enough water. The leaf fall is most likely a result of the current drought following on the heels of ample spring rains.  I’m seeing lots of area trees shedding leaves as the drought goes on here.  The excellent winter and spring rains we had encouraged lots of lush foliage on our trees.  As a natural defense in the face of diminishing water availability, local trees are doing what plants do in this situation, they’re defoliating to reduce transpiration and protect the organism. 

Third, through researching the problem of early leaf abscission – what you’ll find in scientific writings describing leaf drop – there are several other possible causes:

  1. Nitrogen deficiency causes leaves to yellow and in serious cases to fall off. 
  2. Downy spot can cause early leaf loss in susceptible cultivar like 'Stuart', 'Pawnee' and 'Moneymaker'.  It’s possible our wet spring gave this fungus a foothold.  
  3. The Twig Girdler insect can cause small twigs to drop in late summer. Check to see if  the leaves are attached to a small portion of the twig. There will be a perfect circle cut in the bark if this is the culprit.  

This question falls under the bailiwick of State Agriculture Extension Services and I found several useful  on-line publications.  Check out the following links: 

  1. From Texas A & M – Evaluating Pecan Problems2. 
  2. From the University of Florida - The Pecan Tree  
  3.  From the Dirt Doctor  who researches organic growing methods here in Texas – Pecan Tree

So, although I can’t give you a definitive answer, hopefully this information will assist you in determining why pecan trees in Austin are shedding their leaves prematurely.

 

 

More Trees Questions

What grows in Tampa FL
July 01, 2013 - Please let me know what grows in the backyard in Tampa, FL to provide screening and privacy?
view the full question and answer

Tahitian gardenias (Gardenia taitensis) salt and wind resistance in Hawaii
February 03, 2006 - Are Tahitian Gardenias salt tolerant? We live on a rocky coastline in Hawaii and we get a lot of salt spray.
view the full question and answer

Survivability of birch trees in Texas
August 16, 2006 - Is it known whether Gray birch (Betula populifolia Marsh) will grow in North Texas? It seems like the only birch variety which might - and how short is a "short lifespan" for a tree?
view the full question and answer

Susceptibility of Shumard oaks to oak wilt
March 25, 2006 - I have planted a red oak tree. I am still trying to locate the ID tag for the type. I planted it two or three years ago. I purchased the tree from either Lowes or Home Depot. Is there a type of red oa...
view the full question and answer

Problems with pin oak in Manlius, NY
June 20, 2009 - I bought a pin oak when it was ~5 ft tall. It has lived in clay/rock for the last 6 years--healthy, but didn't grow much (no surprise). This spring we planted 3 small boxwoods a few feet from its t...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center