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
Not Yet Rated

Thursday - June 13, 2013

From: Austin, TX
Region: Southwest
Topic: Non-Natives, Diseases and Disorders, Grasses or Grass-like, Trees
Title: Brown rings on grass under live oaks in Austin
Answered by: Barbara Medford

QUESTION:

There are brown rings in the grass at the dripline on several Live Oak trees in our neighborhood. What causes this? The trees appear healthy.

ANSWER:

You did not say what grass you or your  neighbors have. The rings might be a problem in the grass rather than originating from the tree. We will investigate brown rings in non-native grasses bermudagrass, St. Augustine and zoysia.

Although no grasses do well under trees, oak trees have more of an influence on the grasses. Oak, walnut, pecan and other trees exhibit allelopathy which means they exude substances harmful to competitive plants beneath them. Here is a a previous Mr. Smarty Plants answer on how we feel about lawns under trees. Between the shade, the allelopathy and the competition of extensive root systems for water and nutrients, grass growing under trees is always difficult. Since all three of the grasses we mentioned above are non-native to North America we don't know much about them, but will try to find some research to help you make a diagnosis.

Bermuda Grass: From WalterReeves.com Bermudagrass diseases - brown patch.

Zoysiagrass: From Missouri University - Issues of Zoysiagrass Lawns

St. Augustine Grass: From Cypress Isle (FL) Master Gardeners- St. Augustine Grass, Common Summer Problems.

Of course, if you are growing Bouteloua dactyloides (Buffalograss) or Habiturf they both need at least 5 hours a days of sun and won't be growing under the trees anyway.

 

More Diseases and Disorders Questions

Waxy deposits on Magnolia fuscata from Ethel LA
June 18, 2013 - I have a 4yr old Magnolia Fascata (aka banana shrub)- I noticed that it has small oval shaped yellow waxy deposits on the branches.. I have also noticed small black ants on the branches. The unknown d...
view the full question and answer

Problems with red oak trees in North Central Texas
July 13, 2013 - What is the disease effecting Red Oak trees in North Central Texas; causing them to lose leafs in Spring/Summer and turning the remaining leaves light yellow/lime green in color. Thank you.
view the full question and answer

Why doesn't Diervilla lonicera bloom in Wisconsin?
June 11, 2015 - I have had a Diervilla lonicera in southeastern Wisconsin for at least 5 years. It has never bloomed. Why? It appears healthy.
view the full question and answer

Recently planted Chinquapin Oak with browning leaves in Marlin, TX.
July 31, 2012 - We planted a Chinquapin Oak this in March 2012. As of July 21, 2012, the tips of the leaves on the lower branches are turning brown. We cannot see any insects. There does not appear to be any fungu...
view the full question and answer

Death of mature Eve's necklace in Fredericksburg, TX
July 12, 2010 - A friend mentioned his mature Eve's necklace had died this year. The next day I walked past my own mature Eve's necklace(about 5 years old)and it was dead! What could have happened? Thanks.
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