Native Plants
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.
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.
rate this answer
Wednesday - July 13, 2016
From: Boerne, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Young Mexican White Oak Losing Leaves in Texas
Answered by: Anne Van Nest
QUESTION:
I have a 5 yr old Mexican white oak, 20 ft tall losing its leaves mostly at the top. They turn brown & fall off. It does not lose its leaves in the winter, right?. About 3 ft from the top down is bare, The root flanges are not showing at the base. Could the dirt be piled too high around the trunk? I am letting my hose slowly drip in case it is just too dry. What do you think? Do I have a problem?ANSWER:
Mexican White Oak (Quercus polymorpha), according to the Texas A&M Forest Service says that this tree is only recently discovered in the U.S. (1992) as a native tree species, but widely available in commercial nurseries. Naturally occurring only in one known U.S. population, near the Devil's River in Val Verde county, but more common in Mexico. Now planted widely as a landscape tree.
The leaves are simple, alternate, 2" to 5" long, highly variable, but often with several shallow lobes or teeth towards the tip. Leaves are thick, leathery, and semi-evergreen, with distinct raised veins on the yellowish underside. New leaves in spring are peach-colored and in colder climates the leaves are late-deciduous and turn yellow-brown.
The Native Plant Database lists this tree as Monterrey Oak as well as Mexican white oak and Netleaf white oak.
Your comment about the root flare is a potential problem. Soil and mulch should not be mounded up around the trunk higher than the root flare. Howard Garrett, The Dirt Doctor has information and images on his website about Root Flare Management that may be of help to you in determining if your tree is planted too deeply.
From the Image Gallery
More Trees Questions
Controlling native chickasaw plum
July 23, 2008 - How do we kill the chickasaw plum? We have an abundance and want to get rid of them.
view the full question and answer
Small tree for container near pool in Houston
June 24, 2010 - Can you recommend a small tree that I can grow in a pot for shade? Looking for minimal mess because it will be near the pool. How big should the pot be?
view the full question and answer
Cherry laurels next to retaining wall in Austin
September 18, 2010 - My neigbors have 2 cherry laurel trees in their back yard planted within 4 feet of my retaining wall and fence. I am worried the root system will damage my retaining wall. The branches are already pus...
view the full question and answer
Red oaks that didn't drop leaves in Austin
April 04, 2012 - I have a number of Red Oaks on land that did not drop leaves this past fall. Now these same trees seem to be dead? It seems there's some type of mold/fungus on the trees. Some trees have small patche...
view the full question and answer
Fruit on Mexican olive in Austin
June 05, 2008 - Does Mexican Olive set fruit in Austin? Does there need to be a male and female tree or not. How old does the plant have to be to set fruit? Mine is three years old but no olives. I need to know ...
view the full question and answer
| Support the Wildflower Center by Donating Online or Becoming a Member today. |