Host an Event Volunteer Join Tickets

Support the plant database you love!

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

Thursday - June 13, 2013

From: McKinney, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Trouble with live oak in McKinney, TX
Answered by: Nan Hampton and Eric Beckers

QUESTION:

We moved into a suburban home with a live oak tree with a trunk diameter of about 50". I noticed recently how yellow the leaves look compared to the other live oak in the yard. There is not a pattern of yellow on the leaves, they are just almost uniformly yellow throughout each leaf and throughout the tree. Our soil contains a lot of clay. I believe the tree needs treatment with iron. My questions: does it sound like the tree needs iron, and if so, is there any way we as homeowners can treat the tree? Are there supplements available and would we have the tools to apply them?

ANSWER:

There are two oaks with the common name "live oak" that occur in Texas—Quercus virginiana (Coastal live oak) and Quercus fusiformis (Escarpment live oak).  Neither occur naturally in Collin County but probably your live oak is Q. virginiana that was planted as a small landscape tree and, judging by its size, could be 100 years old—or maybe even more.  According to the Smithsonian Marine Station at Fort Pierce, by 70 years of age Florida coastal live oaks can reach a diameter of 54 inches.   However, I suspect your tree is rather more than 70 years old since it is growing in a cooler and less humid climate than the Florida coast.  A venerable tree of this age certainly deserves special care.  With that in mind I contacted Eric Beckers with the Texas Forest Service for his insight and advice.

He suggested that if you feel strongly that you have a soil deficiency of some sort, you should have the soil tested.  Contact your Collin County AgriLife Extension Service office to learn how to get a soil test done.

One pest-related possibility he suggested was:

"After an initial springtime defoliation by a pest (often unnoticed by the landowner) a live oak's second flush of leaves will often look pale in comparison to it's neighbor that still supports an original crop of dark green, glossy leaves.  Look for the multitude of half-chewed leaves and tender new growth and give them a few more weeks to mature and darken up."

Eric also pointed out that Quercus stellata (Post oak), a very common tree in Collin County, looks chlorotic (yellow) early in the season and gets its rich dark green color later in the summer.

Finally, it is not very effective for us to try to help you preserve such a valuable tree by trying to diagnose your problem from afar.  We strongly recommend that you get an onsite inspection by a certified arborist to determine what treatment your tree might need.

 

From the Image Gallery


Coastal live oak
Quercus virginiana

Escarpment live oak
Quercus fusiformis

Post oak
Quercus stellata

More Diseases and Disorders Questions

Knots on redbuds in Stillwell, OK
April 07, 2011 - My redbud has knots all over the limbs. Its been this way for a few years now. I can not find a way to take care of this problem. I don't even know what is causing this. Can you help me?
view the full question and answer

Problems with Thuja in Oakland CA
December 16, 2010 - I have a Thuja hedge about 100' long. Part of this hedge and a well established Rhododendron have been diagnosed with Armillaria mellea that is spreading. I see the bunches of mushrooms growing eve...
view the full question and answer

Insect infestation of plants, dog and home
September 14, 2008 - I have plants that some kind of bug is killing them, my fan plam, ficus tree and other plants. The leaves are drying up and falling off. Apparently, they also are infestion my apartment. I feel them c...
view the full question and answer

Problems with non-native artichoke from El Paso, TX
May 25, 2014 - I have a five year old artichoke plant in the ground that gets sun and some shade, has plenty of fertilizer and compost. Gets enough water. It has been beautiful in years past and last year had 10 a...
view the full question and answer

Why are my lemon Cyprees trees turning Black?
April 01, 2010 - I have 3 lemon Cypress plants - all are about 6 feet tall. One of them has started turning black on one side - like it's been burnt. The inside of the plant is also turning black. I assume something ...
view the full question and answer

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