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?


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

Tuesday - January 22, 2013

From: LaGrange, TX
Region: Southwest
Topic: Problem Plants, Grasses or Grass-like, Herbs/Forbs
Title: Need help fighting grass burs in La Grange, TX.
Answered by: Jimmy Mills


I have 4 acres of wildflowers planted in my front yard. Unfortunately, grassburs have crept in & I need to control them with a pre-emergent. Will this keep the wildflowers from blooming? Also, would like to apply a fertilizer, & the same question applies - will this affect my wildflowers?


Grass burs have many common names, some of which we won’t mention in this space. There are at least 11 species listed in the USDA Plants Database, but the one you are dealing with is most likely Cenchrus spinifex (Coastal sandbur) (see distribution map) , or perhaps Cenchrus echinatus (southern sandbur) (see distribution map). 

Grass burs are considered to be summer annuals and can be controlled either chemically or mechanically. Pre-emergent herbicides offer a good means of chemical control of these weeds by preventing seed germination. Many of your wildflowers are also annuals however, so the timing of application is critical so you aren’t also preventing the wildflowers from germinating as well.

Mechanical control involves pulling (or digging) up the grass burrs before they flower and set seed. Cutting off the flower stalks before the seeds mature is also effective.

I’m going to refer you to a couple of links,  and a couple of answers to previous questions that will help flesh out these strategies.

The first link is to Texas AgriLife Extension, Aransas County Office, and has a thorough discussion of the problems and some cures for sand burs.

This link to Aggie-horticulture includes information concerning herbicide use.

These two answers to previous questions should also prove helpful



Another source of help is the Fayette County Office of Texas Agrilife Extension.


From the Image Gallery

Grass bur
Cenchrus spinifex

More Herbs/Forbs Questions

Colorful flowering plants in shade of live oak in Louisiana
November 29, 2013 - What colorful flowering plants can be grown near the shady base of live oak trees in the Deep South?
view the full question and answer

Plants for a mixed border in Houston
February 22, 2010 - I live in Houston and have a flowerbed I'd like to fill with plants that will look good year-round. The back is already lined with 6-foot shrubs so nothing like that. I'd like something with colorf...
view the full question and answer

Will the
May 27, 2015 - I'm becoming interested in rain gardens, and although Silphium perfoliatum does not appear to be a host for butterfly caterpillars and like most of the "giant tall grass prairie daisies" may be a b...
view the full question and answer

Silver ponyfoot becoming invasive in College Station TX
May 08, 2013 - How can I control or get rid of an established Dichondra groundcover? I bought a few plants of D. argentea from your sale a few years ago, and in that time they've done really well in the area I plan...
view the full question and answer

Ground cover under Spruces from West Chester PA
December 06, 2012 - Trying to get a native groundcover (or any grass/wildflower/fern) planting established under a small stand of spruces. Established stand (30+ years old), so lots of needles on ground. Just about tot...
view the full question and answer

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