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Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

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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

QUESTION:

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?

ANSWER:

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

   #878

   #7105

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

 

From the Image Gallery


Grass bur
Cenchrus spinifex

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