En EspaŅol

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
Not Yet Rated

Wednesday - September 22, 2010

From: Austin, TX
Region: Southwest
Topic: Invasive Plants
Title: Fighting Sandburs with Bluebonnets in Austin, Planting Bluebonnets in Caliche soil
Answered by: Mike Tomme and Barbara Medford

QUESTION:

Mr. Smarty Plants, In my continuing fight against sandspurs I've decided that if I plant a copious amount of bluebonnets seeds that the foliage will choke out the sandspurs because bluebonnets set foliage in the late fall and early winter and will choke out any sandspur seedlings before they can take hold in the spring. Is my logic super flawed? What is the likelihood that bluebonnet seeds planted in September will flower in March when planted in caliche soil?

ANSWER:

Mr. Smarty Plants would never tell you that your logic is flawed. However, Mr. Smarty Plants doesn't think your idea will work. Sandburs (aka sandspurs, grassburs and a bunch of unprintable names) are just too tough. A little bit of shade and crowding won't stop them. They'll just grow right up through the bluebonnets and the two will thrive together. Think of the fields of bluebonnets you've seen and how, late in spring when the bluebonnets fade, the grasses come right back. Sandburs are a grass and they will do the same.

The sandbur you have is most likely Cenchrus spinifex (Coastal sandbur). This plant grows throughout the southern United States and Mexico. It favors poor soils, like caliche, and does well in recently disturbed areas. 

Control of sandburs is is most reliably achieved by hand pulling and, in the longer run, by improving the soil by adding organic matter and eliminating compaction. For hand pulling, learn to recognize sandburs when they have not yet produced the burs, or seeds, so you can pull them out as the opportunity arises. Here is a site that has more information about control of sandburs.

As for your question about planting bluebonnets (Lupinus texensis), early October is the best time to plant seeds. Bluebonnets do well in caliche soils. Here is a how-to article on growing bluebonnets.


Cenchrus spinifex

 

More Invasive Plants Questions

Removing St. Augustine, replacing with native plants
October 06, 2007 - Hello Mr. Smarty Plants, always excited to talk to the Green Guru himself. I've recently purchased a house in South Austin and am interested in establishing a small, 500+ sq ft, prairie grass and wi...
view the full question and answer

Removal, spread of native mistletoe
January 24, 2009 - My neighbor has a lot of mistletoe growing in a tree in her front yard. I have a tree in my yard that has mistletoe in it. Each winter I have the plant removed so birds won't spread it around. Do you...
view the full question and answer

Why are our Euphorbia myrsinites plants dying in Soquel, CA?
August 02, 2010 - Some of our Euphorbia myrsinites die in our garden for reasons we cannot understand. Do you have any explanation or suggest area we should be looking for?
view the full question and answer

Killing oak sprouts from El Paso TX
August 16, 2011 - I want to know how to kill oak root sprouts and seedlings. Very dense and out-of-control in huge area of front lawn. I had tree cut down and I still cannot get rid of them. They're only getting wors...
view the full question and answer

Bald cypress causing problems in Spring TX
June 22, 2010 - There is a 50+ ft Bald Cypress growing near my property line. While the tree has grown substantial knees along the driveway and some as far as 35 ft from the tree in my flower beds, I do not see any d...
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 | STAFF
© 2015 Lady Bird Johnson Wildflower Center