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?


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

Saturday - September 15, 2012

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Bark problems with Monterrey oak from Austin
Answered by: Barbara Medford


I planted a 65 gallon Monterrey Oak (White Oak) in my front yard in February of this year. I water it once a week. All of the leaves and branches appear very healthy and there is no discoloration. About a month ago I noticed some dark areas (patches) on the bottom 5 feet of the trunk. They are not soggy or wounds, just discolored areas. They also don't appear to have a thick layer of bark. Well, about 2 weeks ago I also noticed a small hole with dark sap coming out of it. I have not observed any bugs on the tree or any bug trails. I also haven't pruned or injured the tree in any way. The discoloring and sap are on one side of the trunk ranging from 6 inches to 4 feet of the ground. I would like to know what you think it is?


First, we would comment that is a heck of a big tree to transplant; luckily, you did it in February, so hopefully we can rule out transplant shock. Maybe.

We have recently answered a couple questions on white oaks (Quercus polymorpha (Mexican white oak, Monterrey Oak) and Quercus laceyi (Lacey oak), both considered resistant to Oak Wilt, but with some similar problems. First, we would ask that you read both of these previous questions, to see if they answer your question.

Austin, TX

San Antonio, TX actually, this is on a Lacey Oak, but it is also a white oak,  considered resistant to oak wilt, but it is a very similar problem

Beyond that, the little hole could be caused by a woodpecker or sapsucker who are shopping for either bugs or the sap in the bark of the tree.

Holes in ash in Austin

Holes in pecan branch in Cooper, TX

In the final analysis, diagnosing a tree we cannot see is a near impossibility. If the situation appears alarming enough, you should contact some of the specialists that are mentioned in the various links.


From the Image Gallery

Monterrey oak
Quercus polymorpha

Monterrey oak
Quercus polymorpha

Monterrey oak
Quercus polymorpha

Lacey oak
Quercus laceyi

Lacey oak
Quercus laceyi

Lacey oak
Quercus laceyi

More Trees Questions

Are Rhododendrons and Mountain Laurels native to the Texas/Mexico Border?
July 05, 2012 - I'm trying to determine whether Rhododendrons, azaleas and mountain laurel grow around the Texas/Mexican border. Are they native to this region?
view the full question and answer

Juniperus virginiana and some pines for Florida
July 11, 2007 - I live in Pensacola, FL (Northwest Florida, practically lower-coastal Alabama) and I am looking for a medium size tree that will cast shade on my home. The house faces due west and it gets extremely h...
view the full question and answer

Transplanting a redbud in Boerne TX
August 29, 2012 - Hi there, My question is when is it safe to transplant a native tree? I have a redbud tree come up in m flower bed I want to try to transplant it instead of cutting it out. It is very young - maybe 4-...
view the full question and answer

Control of live oak suckers by cutting
July 23, 2007 - How do I control the Live Oak root suckers? At the moment we are cutting them as they come out of the ground.
view the full question and answer

Using cedar chips as mulch in Wimberley, TX
August 19, 2010 - In TX Hlll Country there is an abundance of wood chips, usually "cedar", which I have used as plant mulch. Since wood chips extract nitrogen to decay, do you consider chips a poor choice as plant m...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2015 Lady Bird Johnson Wildflower Center