Contact Us Host an Event Volunteer Join

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
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

QUESTION:

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

ANSWER:

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

Cedar Elm trees for Rockport, TX
January 08, 2010 - Cedar Elm trees for the Gulf Coast area? I live alongside a fresh water lake with sandy soil that is 2 miles from the bays. Along the shoreline, I'd like to replace a Weeping Willow that is in decl...
view the full question and answer

Desert willows in Florida
December 07, 2007 - I'm in Dunnellon, FL and I'm growing several chilopsis linearis from seeds, but they are coming in long, tall with very few leaves. and continuously fall over from their lanky growing ways. Any idea...
view the full question and answer

Viability of Desert Willow and Hong Kong Orchid Tree in Spring Branch, TX
December 26, 2006 - We live in Spring Branch, Rt 281 north of San Antonio. We want to plant a Regal Desert Willow tree and a Hong Kong Orchid tree. Will the cold / freeze be a problem? Where locally can we purchase th...
view the full question and answer

Distressed Red Oak tree in Pflugerville, TX.
July 22, 2012 - I have a large (40 ft) Red Oak tree in my yard that is distressed. It started with yellowing leaves, with darker veins. Then small brown spots appeared, followed by browning arount the leaves edges. N...
view the full question and answer

Are mountain laurel beans safe to use as rattles with small children?
September 19, 2012 - Is it safe to use the mountain laurel mescalbean pods as shakers or rattles, as long as the pods are not open and the seeds left unexposed? If a small child (very small, who has no way to open the ...
view the full question and answer

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