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 Compost and Mulch Questions

How to grow milkweeds (Asclepias spp.) for monarch butterflies
March 31, 2010 - I tried and tried and tried to grow Asclepias viridis, A. asperula and even A. oenotheroides from seeds and even tubers for fourteen years! Do you have advice for growing these and other milkweed plan...
view the full question and answer

Landscaping help for Gilmer, TX
September 01, 2008 - We have just moved to the beautiful hot state of Texas from warm California and we need some help! Our roses are dying, we have a patch about 25ft. by 3ft. that gets the rain run off like a little str...
view the full question and answer

Ground cover to withstand dog traffic in Michigan
November 02, 2010 - I need a soft ground cover that will grow in sand, and be able to take four big dogs that love to run in the yard. Grass just doesn't make it. Someone suggested that groundcover might work. Thanks...
view the full question and answer

Non-native, invasive creeping fig in Webster TX
May 26, 2013 - We've recently moved into a new home in the southeast Houston area. The back of our property has a long concrete wall (gets quite a bit of sun), which we thought we could cover with a spreading vine....
view the full question and answer

Combining native shrubs for hedge in Austin
April 15, 2009 - Smarty, Please tell me what the definitions are for all the various water, soil moisture, drainage and light requirements mean. Are the definitions global? I live in Central East Austin and inten...
view the full question and answer

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