En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Getting rid of invasive grasses in backyard

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
1 rating

Saturday - July 17, 2010

From: Austin, TX
Region: Southwest
Topic: Invasive Plants
Title: Getting rid of invasive grasses in backyard
Answered by: Nan Hampton

QUESTION:

Mr. Smarty Plants, How do I rid my yard of invasive grasses? I am finding Bermuda, stickers, crabgrass and maybe even Johnson grass throughout my backyard. The invasion is substantial in one 200+ sq ft area. I haven't mowed all summer because I was letting my wildflowers go to seed. Should I use a selective herbicide? If so will it hurt the lizards and toads? At what height should I mow both that area and my Indian paintbrushes, native verbena and brown-eyed Susans? Thanks

ANSWER:

Mr. Smarty Plants is sorry to tell you that getting rid of all these invasive weeds is not going to be easy.  Just a few days ago I wrote the answer to a question about getting rid of the non-native Cynodon dactylon (bermudagrass) in a lawn.  Bermudagrass is especially difficult because it spreads by seeds, stolons (above ground stems) and by underground rhizomes.  The advice in the previous answer stands for your bermudagrass. Sorghum halepense (johnsongrass) is another non-native invasive that is able to spread by two methods similar to bermudagrass—by seeds and by underground rhizomes. 

By stickers I assume you mean sandburs.  There are several species of sandburs, but I suspect you have Cenchrus spinifex (coastal sandbur).  It is important to remove the seeds (these are within the stickerburs) before they drop to the ground.  Since this is an annual species, it must drop its seeds to come up again.  Here is more information about Cenchrus sp. from California and ways to control it. You can also dig out and pull up the plants, but the most important thing is to not let the burs fall to the ground.  Digitaria sanguinalis (tall crabgrass) or Digitaria ischaemum (small or smooth crabgrass) also reproduces by seeds so it is important to remove seed heads before they mature.  This is also important for all your invasives—don't let them go to seed!

For all the invasive species you named you will need to use multiple control measures consisting of physically removing as many plants as possible (is there a teenager in your neighborhood who needs a summer job?), making sure that all the seed heads are removed before they mature, and judiciously using herbicides (see the suggested applications in the different control articles linked above for guidance).  You will need to be persistent and diligent.  If you think that this is too daunting, you can always use solarization to kill everything and start completely over.  The Native American Seed website has a very good description of how to do this in their article, Planting Tips for Native Grasses.  Here is another take on Soil Solarization from University of California-Davis.

There is some evidence that amphibians (e.g., toads, frogs and salamanders) are negatively affected by one of the most widely used herbicides, glyphosate, and the particular surfacant that is used to carry it. The risk could be lowered by painting on the herbicide with a small brush or sponge applicator rather than by spraying it.

For mowing, you will want to wait until most of your wildflowers have set and dropped their seeds.  You might find the How to Article, Meadow Gardening, helpful for advice about maintaining your meadow-like lawn.  Also, you don't want to mow too short—leaving your grasses and wildflowers several inches high (at least 4 to 6 inches) can help control bermudagrass and crabgrass since neither plant grows as well when shaded.

Finally, the Greater Madison Healthy Lawn Team (Madison, Wisconsin) has a very good treatment of Weed Control Methods using corn gluten, homemade herbicides made from liquid soap and vinegar, and solarization.

Good luck!

 

More Invasive Plants Questions

Smarty Plants on invasive and exotic plant species
March 26, 2004 - Where can I go to learn more about invasive and exotic plant species?
view the full question and answer

A&M maroon bluebonnets for Hawaii
July 10, 2011 - My daughter graduated from Texas A&M and has moved to Hawaii. She would love to have the maroon bluebonnets developed by A&M to plant in her new home. How would she need to prepare the seeds since t...
view the full question and answer

Invasives species experiment from Fairfax VA
May 09, 2013 - Dear Mr. Smarty Plants, I have some friends that need an experiment on Invasive Species fast. They are in 11th grade at Robinson secondary school. Are you able to help? Its due in June and they don'...
view the full question and answer

Control of Acacia escaping cultivation in California
March 26, 2007 - My backyard has been overrun by acacia shrubs. How and what can I do to permanently rid the area of this weed? I hold an agricultural QAL so I have access to herbicides if there are effective ones a...
view the full question and answer

Help with control of small, invasive groundcover
April 16, 2012 - I have a very invasive ground cover creeping into my yard. I've tried to identify it and it's similar to creeping charlie or garlic mustard. Leaves are triangular with jagged edges, small purple f...
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