En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Texas Pistachio trees dropping leaves in Austin

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

Wednesday - June 09, 2010

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders, Transplants, Watering, Trees
Title: Texas Pistachio trees dropping leaves in Austin
Answered by: Barbara Medford

QUESTION:

I have several Texas Pistachio that are about 13 years old. Despite good rainfall in Travis county this year, they seem to be losing most of their new leaf growth now in early June. Leaves are simply yellowing and dropping much as they would in the winter. Any idea what the problem could be?

ANSWER:

While Pistacia mexicana (American pistachio) is native to Texas, this USDA Plant Profile shows it growing in only one county in the Big Bend area. That doesn't mean it won't grow in Austin, because obviously they do, at least for 13 years anyway. If they had not gone ahead and leafed out in the Spring, we would have blamed the very unusual cold temperatures we had this past winter. That could still be the problem.

What we have to do is try to discover what happened between last year and this year that could be causing this. For instance, has some kind of herbicide or "weed and feed" fertilizer been spread on your grass to get rid of broad-leafed weeds? Trees are also broad-leafed plants, and a too-vigorous application or (in the case of spraying) a brisk wind might have caused the leaf drop. Of course, if the same conditions don't apply to all the trees showing stress, that is probably not the only cause of the problem. Another clue we found said that the pistachio could flourish for years in the right location,and suddenly die of root rot from too much moisture in the soil. Have you put in a sprinkler system or started wateriing more often? We had several dry years and then a more normal rainfall. If the drainage in your soil is not good, the roots of the pistachio could be drowning. Desert trees do not flourish in lush conditions. 

Finally, take a good close look at the tree. While we found no documentation of disease or insect pests bothering this plant, it's always a possibility.  Beyond that, we are out of ideas. If you are watering more, we would suggest you direct it away from your trees. You might try treating it like transplant shock, and trimming away some of the upper portion of the trees. If the roots are struggling, this could help them get the needed moisture up to the leaves so the leaves can continue to manufacture food for the whole plant. Don't fertilize.The last thing stressed roots need is stimulation to put on new growth when they are just trying to stay alive. 

Fiinally, we suggest you contact the Texas AgriLIFE Extension Office for Travis County and see if they have encountered similar problems in the neighborhood.

From our Native Plant Image Gallery:


Pistacia mexicana

Pistacia mexicana

Pistacia mexicana

Pistacia mexicana

 

 

 

 

More Watering Questions

Mites in soil of house plants
June 25, 2008 - Hi there! I recently noticed tiny silver mites in the soil of my plants that I only notice after watering. These plants are indoors in on a window ledge (a dwarf palm, aloe plant and Hawaiian Scheffle...
view the full question and answer

What fertlilizer for live oaks under drought conditions?
July 01, 2011 - In your June 7 answer about helping live oaks survive the drought, you state that additional fertilization may help as well. What kind of fertilizer to you recommend and how should it be applied? Th...
view the full question and answer

Decline of indoor lemon cypress
June 25, 2008 - I received a lemon cypress as a gift. I have kept it indoors in bright light and tried to keep it moist. When I received the plant the foliage was soft and now it has become brittle and dry even tho...
view the full question and answer

Redbud leaves turning yellow in mid-summer
July 13, 2012 - The leaves on our redbud trees are turning yellow. The yellow leaves are pale with no other spots and no dark veins. I don't know for sure which variety of redbud they are or how old they are (more t...
view the full question and answer

Drought tolerant Plants and moving Wax myrtles in Austin
April 30, 2011 - Mr. Smarty Plants, What are the most fire resistant and drought tolerant plants for caliche soil in Austin area? I am considering relocating or removing my wax myrtle shrubs because they are ...
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
© 2014 Lady Bird Johnson Wildflower Center