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
1 rating

Friday - July 13, 2012

From: Denton, TX
Region: Southwest
Topic: Diseases and Disorders, Watering, Trees
Title: Redbud leaves turning yellow in mid-summer
Answered by: Guy Thompson

QUESTION:

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 than 10 years old). The heat and drought of 2011 hit us pretty hard. Is this a result of last year's drought, or is there something else going on? What can we do to save them? Thank you!

ANSWER:

Redbuds and many other trees normally drop some leaves early when drought-stressed.  This is an adaptation to reduce the need to take up moisture from the dry soil.  Don't worry too much if the branches are still alive (scrape off the bark on a defoliated twig to see if it has green and moist tissue) and if 50 % of the leaves remain green.  New leaves will appear next spring.

If a great number of leaves are turning yellow, the trees may still be drought-stressed.  Drought stress can show up even a year or two after a drought because part of the root system has not yet recovered.  If that is the case, you should make sure that the soil around the trees remains moist.  Deep watering throughout the root zone (out to the drip line) once a week will assure that the trees are not short of water.  Mulching the area under the trees will help conserve soil moisture.

Plant nurseries around the country sell several varieties of redbudCercis canadensis var. texensis (Texas redbud) is more drought-resistant than Cercis canadensis (Eastern redbud) and less drought-resistant than Cercis canadensis var. mexicana (Mexican redbud).  The seed pods of Texas redbud tend to be reddish in color while the Eastern redbud seed pods remain green.  That may help you identify yours.

Drought stress would make the trees more susceptible to disease.  It is possible that you trees are not drought-stressed but suffering from verticillium wilt.  Here is a web site on this subject. 

Good luck in keeping these attractive trees alive!

 

From the Image Gallery


Texas redbud
Cercis canadensis var. texensis

Eastern redbud
Cercis canadensis

Mexican redbud
Cercis canadensis var. mexicana

More Trees Questions

Ash tree dying back to lower sprouts in Kempner TX
June 19, 2010 - My 2 year old ash tree leaves dropped, appears dead, branches dying. New growth near base of tree. Do I cut upper trunk or remove entire tree? My other ash is doing well.
view the full question and answer

Smoketree not flowering in Beverly Hills CA
June 29, 2011 - Why is my Smoke tree not flowering? It is big and the leaves are beautiful but no blooms.
view the full question and answer

Oak bark problems from Stillwater OK
May 14, 2012 - In my clients large oak tree there is bark stripped from the limbs in small pieces. No piece is larger than 1 inch by 1 inch and occurs on limbs high in the canopy. It does not look like squirrel doin...
view the full question and answer

Are Black Olive trees safe to have in pastures in Florida
May 06, 2009 - I am trying to find out if Black Olive trees will be safe to have in our yard and/or pastures. We raise cattle, goats and horses. We need to find some good shade trees that are safe for our animals ...
view the full question and answer

Tree ordinances re Magnolia Ladybird Johnson tree
July 02, 2006 - What exactly is a Ladybird Johnson tree? Also, is there any type of federal or state law(s) that prohibits the cutting, trimming or removal of a LadyBird Johnson tree? Thank you for your time!
view the full question and answer

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