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
2 ratings

Wednesday - July 13, 2011

From: Harlingen, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Treating suspected drought-stressed live oak
Answered by: Guy Thompson


I have a live oak with excessive leaf drop - it was planted approx. 20 year ago surrounded by heavy pavers. very little grass - I did not plant the tree - I have noticed in the last few years the drop increases - the oaks I have in the back yard only shed during the winter, we have long hot summers. I can removed the pavers. Thank you


There is no question that even old, well-established trees are going to need some extra help during the kind of drought we are having right now. If the pavers around your tree are set close together, water permeation may be sharply curtailed.  Mr. Smarty Plants recommends that you remove as many of the pavers as possible, right out to the drip line of the tree. Replace the pavers with 2-3 inches of mulch to slow the evaporation of soil water.

Many trees have been saved in past droughts by additional  watering in late summer. As the underlined article suggests, professional arborists suggest deep watering, and the amount of water applied would depend on your soil type, e.g., rocky or clay.  The trees might also benefit from additional fertilization.  Furthermore, trees suffering from drought stress are often more susceptible to insect and fungal attack.

This University of Illinois Extension website Dealing with the Drought affirms that watering even drought-resistant trees like the oak is essential. It points out that a 90 ft. oak tree will be a lot worse to lose than annual flowers or vegetables. We don't recommend watering at the base of the trunk, but watering farther out, with a hose or sprinklers, probably about every two weeks. An excerpt from this website will tell you why:

"Our 90-foot oak example could have roots at least 40 feet beyond the tree’s
drip-line. The same goes for most shrubs. So, apply water at the tree or
shrub’s drip-line, not at the trunk."

Those roots may be pretty deep, and part of the protection of the trees, but much of the root system is in the top 12 inches of the soil. So, putting the water out there helps to avoid fungus and rot at the base of the trunk.


From the Image Gallery

Escarpment live oak
Quercus fusiformis

Escarpment live oak
Quercus fusiformis

Escarpment live oak
Quercus fusiformis

More Trees Questions

Will lilacs survive in Houston?
October 26, 2009 - My wife loves the smell of Lilacs (we're originally from Oregon), but we don't see any here in Houston. Is it possible to get lilacs to survive in Southeast Texas?
view the full question and answer

Best time of year to trim oak trees from Beloit WI
July 23, 2010 - What is the best time of year to trim oak trees?
view the full question and answer

Irish Strawberry tree care from Sydney Australia
April 15, 2012 - Hi I have an Irish Strawberry tree - AKA Arbutis Enedo. I have had it for a couple of years now, I have it planted in the ground quite healthy soil, I feed it Dynamic lifter (chicken manuare/pellet f...
view the full question and answer

Texas persimmon with scorched leaves from Austin
July 11, 2013 - I planted a Texas Persimmon seedling (five gallon) in my yard in early April. It is in a sunny, well-drained spot, and I have watered it regularly since planting. All was fine until the last weekend i...
view the full question and answer

Is western soapberry (Sapindus saponaria var. drummondii) dioecious?
February 15, 2008 - Hi! I found different information on the flowering habits of the western soapberry, Sapindus saponaria var. drummondii. Is it dioecious or polygamo-dioecious or none of them? I have some little seed...
view the full question and answer

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