Rent Shop Volunteer Join

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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

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

Growth in oak tree in San Antonio
April 05, 2011 - We have a very large gorgeous oak tree in our backyard here in San Antonio, Texas. I noticed a thickness high up in the tree. Thinking it was a nest of some sort, I used binoculars and saw a parasiti...
view the full question and answer

Illegal to remove an orange blossom from ground in Florida from Atlantis FL
March 28, 2012 - Is there any law that prevents someone from removing an orange blossom from the ground in Florida?
view the full question and answer

protecting native trees during drought
June 07, 2011 - We are very concerned about our mature live oaks and cedar elms because they are so stressed due to the drought. We have lost several of our mountain juniper and I really don't want to lose our more...
view the full question and answer

Repairing Previous Silver Maple Pruning Damage
May 09, 2015 - I cut a limb off my silver maple wrong and now the trunk is developing a hole. What is the best treatment?
view the full question and answer

Falling Balls from an Oak in Kingsland TX
May 25, 2015 - I have a large Live Oak in the back yard, with St. Augustine grass under it. It is April 3, 2015. The leaves have fallen and now little tiny round balls are falling. I am hearing a popping noise und...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.