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: 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 Trees Questions

Correction of tree name from Bay Point CA
October 16, 2013 - The tree should of been Mulberry don't know how it was changed!! Tuesday - October 15, 2013 From: Bay Point, CA Region: California Topic: Non-Natives, Cacti and Succulents, Trees Title: Non-...
view the full question and answer

Non-native invasive carrot wood tree losing leaves in Alpine CA
April 22, 2014 - My carrot wood tree is losing all of its leaves. The tree is about 15foot high & 13 years old. Could it be gophers? The tree was trimmed 1 year ago.
view the full question and answer

Possible reasons for non-fruiting wild plum
March 10, 2007 - My grandfather has land in Lee County with thickets of wild plum, I believe creek plum is another name. However, they never seem to produce plums while thickets nearby on the roadside less than one mi...
view the full question and answer

Problems with red oak from Austin
July 31, 2013 - I planted 3 Texas Red Oaks several years ago. The trees are in a tight cluster just a few feet apart. At the end of last summer, one of them began to develop brown spots and yellowed leaves. This summ...
view the full question and answer

Failure of Bald Cypress to fully leaf out
April 14, 2008 - My family just moved to a house in Burnet County, about 7 miles south of Bertram, close to the Balcones Canyonlands NWR, with very rocky limestone soil. We bought several trees last fall, including a ...
view the full question and answer

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