En Espa—ol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
6 ratings

Tuesday - March 22, 2011

From: San Antonio, TX
Region: Southwest
Topic: Invasive Plants, Problem Plants
Title: How to get rid of nut grass from San Antonio
Answered by: Barbara Medford

QUESTION:

We just had a house built on a lot that was mostly rock. The small back yard has a berm on which they brought in soil then mulched it. Now we are getting all sorts of weeds through the mulch, what my husband calls "nut grass". How can we get rid of the nut grass?

ANSWER:

Oh, boy, it's nut grass season again. You can almost set your calendar by the time we start to receive questions about how to get rid of nut grass.

Purple nutsedge (Cyperus rotundus) is a sedge native to Africa and central Europe (north to France and Austria), and southern Asia. It is considered one of the most invasive weeds known, having spread out to a world-wide distribution in tropical and temperate regions. The difficulty in controlling it is due to its intensive system of underground tubers and resistance to most herbicides. Tubal dormancy is perhaps the most important of the adaptations that enable nutgrass to persist. That is why nutgrass can re-emerge after you thought you had eliminated it by herbicide or weeding.

Some of the suggestions made by experts on how to control this pest include making sure the drainage of the soil is good. It is also supposed that it can be shaded out by vegetation around it. Populations of viable nutgrass can be dramatically reduced by repeatedly turning the soil at one to two-week intervals to expose the tubers to the sun. Unfortunately, in your  situation, these are probably not terribly practical. As noted above, the tubers are resistant to most herbicides, and if the blades of "grass" are broken off, the tuber carries on, and one to two inches of new growth will be visible within a day. Oh, and it's one of the few plants that plastic mulches cannot affect.

It would appear that part of the reason this nuisance showed up has to do with your construction of the berm.  Nutgrass tubers can be as deep as 18", and disturbance of the soil no doubt enabled some of those dormant tubers to get close enough to the now-cleared surface and begin to make themselves known. In other words, that berm has been prepared for the thriving of nutgrass, hiding out in that soil. We know you don't want to hear this, but there is no magic cure. If the soil is kept fairly loose and moist, it will be easier to pull out those long strings of tubers. That is about the only satisfying thing about nutgrass, is that you can get a string of the rhizomes and tubers going, and pull out a bunch in one operation. If you were considering getting on your hands and knees to paint with herbicide, it would be just as easy (and much safer for your other plants) to just pull the !*#!* stuff out. And please, no flaming with the propane torch. You could singe those little blades, and fresh ones would pop up from the tubers protected by the earth. Meanwhile, some of your intended plants could be crisped!

 

 
 

More Problem Plants Questions

Eliminating crabgrass in a newly mulched area in Austin
June 26, 2009 - We just had our whole front lawn taken out. We are starting to plant native plants in its place. The idea was to do whatís best for the environment and reduce maintenance. At this point Iím beginni...
view the full question and answer

Bulletproof plants from Burleson TX
April 18, 2013 - I recently wrote you a question concerning planting a privacy plant consisting of wax leaf ligustrum on my country property. Your answer was immediate (thank you-I am impressed). I like the wax leaf ...
view the full question and answer

Elimination of Whitemouth dayflower in Dothan AL
March 18, 2009 - I am infested with Widow's Tears in my yard. I would like to get rid of them. Can you tell me how?
view the full question and answer

Eradication of invasive thistles in Parma OH
July 11, 2010 - Lawn is full of prickly weeds with very deep roots. May be called Scotch Thistle, although id is not confirmed. They will grow as tall as they can amid other plants, and when mowed in the lawn, they...
view the full question and answer

Eradicating Cucurbita foetidissima (wild gourd) in California
August 23, 2013 - I live in San Diego County where the wild gourd/stink gourd roams freely and quickly. Any suggestions on how to eradicate. It is extremely invasive and nothing has worked! Thank you,
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center