Rent Shop 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
7 ratings

Sunday - August 30, 2009

From: Pflugerville, TX
Region: Southwest
Topic: Compost and Mulch, Grasses or Grass-like, Trees
Title: Removing grass under oak trees in Pflugerville TX
Answered by: Barbara Medford

QUESTION:

I would like to use the newspaper-and-mulch method to smother grass under the canopy of live oaks, a bur oak, and a lacey oak so that I can plant natives that will thrive there. However, I'm concerned that this technique will also smother the feeder roots of the trees. Can I do this without harming the oaks, or do I need to pull the grass out by hand?

ANSWER:

Frankly, we're astonished that you HAVE grass under your canopy of oaks. We have dealt with the problem of things growing under oaks several times recently. See this previous answer, dated August 26, 2009, on why plants won't grow under oaks. Another, on ground cover under oaks, dated February 24, 2009. This excerpt from an answer dated Dec. 10, 2008 specifically addresses the failure of grass to grow beneath oaks:

"In general, plants need light (for photosynthesis), water (for photosynthesis and other processes), and minerals (which also help in photosynthesis). The grass growing under your pin oaks could be suffering from lack of sunshine, and it is certainly competing with the oaks for water and nutrients. The shade problem isn't easy to solve, but you can increase the amount of water and nutrients that the grass is receiving. Is the die back new, or has it been going on for some time? If it is new, you might try to determine what conditions have changed?"

Need we go on? You didn't say what kind of grass you have, probably it is non-native St. Augustine if it is surviving at all in all that shade. We don't like non-native grasses, obviously, but this may be a case of "if it ain't broke, don't fix it." If you want to have a go at it, the mulch would be okay, as long as you didn't get it up around the trunk of the tree, where it might encourage fungi and rot. It is an attractive ground cover under a tree, won't smother the roots and, as it decomposes, will in effect be composted to amend and enrich the soil. The newspapers could be another story, and from personal experience, the top layer of mulch tends to get kicked or blown around, and suddenly you are looking at the Sunday funnies and car advertisements all over your property. And they are blowing around too, which isn't going to endear you to your neighbors.  If we were going to advise you on the best way to rid yourself of the grass, yes, pulling it out is the best way. And pulling it out, and pulling it out and pulling.... Grass can be very persistent and, again from personal experience, St. Augustine gets along just fine under mulch. It may be a little paler green from being covered by mulch, but IT'S ALIVE.

 

 

More Trees Questions

Curling lower leaves on live oak in Cedar Park, TX
June 11, 2009 - I have noticed that one of my live oak tree, the leaves on the bottom of the tree have stared to curl. The leaves above that look fine. The trees are about 12 yrs old. Any suggestions?
view the full question and answer

Watering live oak trees from McAllen TX
December 24, 2012 - What are the watering requirements for live oak trees in deep south Texas? How often and how many inches to be applied? One pop-up spray sprinkler spaced approximately fifteen feet away from each tr...
view the full question and answer

Deer-resistant plants for under cedar and oak trees in Austin
June 22, 2010 - I have about 1.5 acres in southern Travis county. It's full of mature live oaks and cedar trees, and the soil is full of limestone. I've been gathering the limestone and using them to create raise...
view the full question and answer

How soon after stump grinding can something else be planted?
January 18, 2009 - How soon after cutting down a Mulberry and grinding up the stump can we plant a new tree in its place?
view the full question and answer

Removing juniper roots from San Francisco
February 13, 2011 - Topic-Juniper Tree Root Removal (agh!) Needs-3 removed yet roots remain, some growing UNDER the cement, driveway and house!!! (under growth = ~3" as far as I can determine, thus far). Question-Do I ...
view the full question and answer

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