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 - November 22, 2013

From: Dallas, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Is post oak resistant to oak wilt from Dallas TX
Answered by: Barbara Medford

QUESTION:

I am confused. The NPIN website says that Post Oak IS susceptible to oak wilt, but all the other information I have been able to find says that it is resistant to oak wilt and rarely gets the diesase. Can you tell me where the information on the NPIN website originates from or if perhaps it is an error?

ANSWER:

Don't feel alone. The facts on Oak Wilt are confusing to everyone. We did find the line on our wepage for Quercus stellata (Post oak) that you mentioned:

"Susceptible to oak wilt. Not often used in landscape situations. Slow-growing and long-lived." The Post Oak is a White Oak.

We will go to another source, texasoakwilt.org, for some clarification, if possible. We suggest you scan the whole site. From the Introduction to that site: "All oaks (Quercus spp.) are susceptible to oak wilt to some degree, but some species are affected more than others." Also from that website:

"Patterns of Tree Mortality

 Most live oaks defoliate and die over a 1- to 6-month period following initial appearance of symptoms. Some live oaks take longer to die, and a few untreated trees may survive many years in various stages of decline. Occasionally, a few live oaks in an oak wilt center may escape infection and remain unaffected by the disease.

Red oaks never survive oak wilt and often die within 3 to 4 weeks following the initial appearance of symptoms. During summer months, diseased red oaks often can be spotted from a distance because of their bright autumn-like coloration in contrast to the surrounding greenery."

From the Texas A&M Forest Service, here is a map of the counties in which oak wilt appears in Texas. Also from that site:

"Oak wilt has been found in over 73 counties and in almost every city in Central Texas, as well as, Abilene, Midland, Lubbock, Dallas, Ft. Worth, College Station, Houston, and San Antonio. It can be a problem wherever live oaks tend to be the predominate tree. It does not matter whether they are transplanted or naturally grown. An individual tree’s age, size or previous health status does not make it more

"Red oaks, particularly Spanish oak (Quercus buckleyi), are very susceptible to the fungus.  White oaks, like post oak (Q. stellata) and bur oak (Q. macrocarpa), are resistant to the fungus and rarely die from the disease."

Bottom line: If you want to add oaks to your landscape, a post oak is probably less  likely than the red oaks and live oaks to contract Oak Wilt. If you choose the post oak or have some on your property that you wish to protect, you should still follow the management policies from the Management section of texasoakwilt.org.

 

From the Image Gallery


Coastal live oak
Quercus virginiana

Coastal live oak
Quercus virginiana

Texas red oak
Quercus buckleyi

Texas red oak
Quercus buckleyi

Post oak
Quercus stellata

Post oak
Quercus stellata

More Diseases and Disorders Questions

Sap oozing from non-native Chinese pistache in San Antonio
September 07, 2011 - I live in San Antonio, and my chinese pistache is exuding copious amounts of a sticky sap from old trim sites and from the trunk itself. The tree is about 12 years old and has been healthy up until no...
view the full question and answer

Will Mountain Laurels be harmed by juglones from my pecan tree?
May 06, 2009 - Hi. I just bought a house. It has a big pecan tree at the edge of the front lawn next to the street. I guess it's about 25 feet from the front of the house. I was thinking of planting mountain la...
view the full question and answer

Problems with purple passion flower
September 04, 2007 - Hello, I live in La Place, Louisiana (30 miles west of New Orleans). In March 2007, I planted a purple passion flower (maypop). During the spring it thrived and was covered with brilliant green le...
view the full question and answer

Fungus type problem on native blackeyed susans in Ohio
August 20, 2008 - I have black eyed susans that have recently developed a black fungus type problem in the bottom and on the leaves. The flowers are now wilting and dying. What is this and how can I stop it from possib...
view the full question and answer

What are the green round growths on the edges of my oak leaves in Fairfax, OK
May 21, 2013 - round growths on the edge of oak leaves. ranging in size from a pearl to a lime. ranging in color from pale green to lime green. hollow, small ones appear to contain one small gnat sized seed. the la...
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