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?

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

Tuesday - July 19, 2011

From: Austin, TX
Region: Southwest
Topic: Compost and Mulch, Watering, Trees
Title: Should Texas live oaks be mulched under drought conditions?
Answered by: Guy Thompson

QUESTION:

Should we mulch our live oaks in pastures for water retention?

ANSWER:

Live oaks are well adapted to Texas droughts, but this year is an exception.  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. Many trees have been saved in past droughts by additional  watering in late summer.  If this is not feasible for you, mulching will indeed help retain the moisture that is in the ground. A two to three inch mulch of ground bark and leaves, especially around the drip line, would be most advisable.

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.  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.

 

 

More Watering Questions

Problem with American Beautyberry in Houston.
July 02, 2014 - My American Beautyberry is dying one branch at a time. The entire plant looks great, now flowering and starting to put out berries. Then one or two branches will completely die. Trim those off, wi...
view the full question and answer

Texas Pistachio trees dropping leaves in Austin
June 09, 2010 - I have several Texas Pistachio that are about 13 years old. Despite good rainfall in Travis county this year, they seem to be losing most of their new leaf growth now in early June. Leaves are simpl...
view the full question and answer

List of plants that tolerate
May 11, 2014 - Could I get a list of "grey water" tolerant shrubs/evergreens/etc? *Full sun
view the full question and answer

Fungus gnats on house plant in Edwardsville IL
July 16, 2009 - I recently purchased a Trailing Perennial Plant, and I am seeing a lot of gnats flying in my house. Could this be the problem?
view the full question and answer

Premature browning of bald cypress needles in summer
July 15, 2011 - I have several 10m high taxodium distichum trees in the lawn, with drip irrigation twice a week, and same soil content, and on just one of them, several leaves have started turning brown, it seems to ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center