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

Comparisons of King Ranch Bluestem and Kleberg Bluestem grasses
September 03, 2008 - Regarding your answer to a question from Wimberly Tx on November 17 2007 about KR Bluestem: Many people confuse King Ranch Bluestem (Bothriochloa ischaemum) with Kleberg Bluestem (Dichanthium annulatu...
view the full question and answer

Non-native, invasive Asiatic Jasmine from Austin
October 25, 2012 - Is Trachelospermum asiaticum considered a native texas plant? Is there an example growing at the Center that can be viewed?
view the full question and answer

Plants for delineating property line
July 18, 2010 - I have a neighbor who does not mow his grass or take care of a strip that runs between my property and his. I would like to plant some inexpensive, low maintenance, shrubs, that would do well in full...
view the full question and answer

How to combat weeds growing in mulch
September 12, 2008 - Trying to decide on either ground cover plants, or some type of gravel. We have a new house where the builder has planted small shrubs in the full sun flower bed next to house. The bed has mulch at th...
view the full question and answer

Problems with non-native Chinaberry tree from Tucson AZ
September 05, 2013 - I have a 30+ year old Chinaberry tree and this year the branches are much sparser with leaves and there are a lot of small dead branches. Should I fertilize and what should I use? Thank you
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center