En Español

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?


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 - 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


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?


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 Trees Questions

Identification of tree in California
May 02, 2012 - A medium-size tree with shiny green leaves toward the bottom and garnet red ones toward the top of the tree. The leaves are narrow with saw-toothed edges. There are clustered small white flowers with ...
view the full question and answer

Need suggestions for a privacy screen besides Murray Cypress.
October 18, 2011 - Mr. Smarty Plants, I live in NE TX, about an hour east of Dallas on I-20. I hear interstate traffic behind my house, and have a busy street on its left side, and a school adjoining in back. I thi...
view the full question and answer

Leaf spot as indicator of Oak Wilt Disease
May 26, 2007 - I live close to the Wilflower Center. I have two trees in my front yard which are just now showing brown spots on the leaves. I fear this may be oak wilt. Would it be possible for me to bring som...
view the full question and answer

Evergreen Trees for Low Maintenance Screen
April 18, 2015 - We live in Pacifica, CA and are looking to plant a row of low maintenance trees in our back yard along our fence, that grow to be a maximum of 15' high, that stay green year round. What do you recomm...
view the full question and answer

Plants to filter dust from a road in MD
June 01, 2011 - I live in MD next to a dirt/gravel access road. I would like to plant something along my property line to block the clouds of dust we regularly get from cars and dirt bikes. Is there something fast ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center