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 - January 30, 2008

From: Carrollton, TX
Region: Southwest
Topic: Plant Identification
Title: Identification of plant, possibly giant ragweed (Ambrosia trifida)
Answered by: Nan Hampton and Joe Marcus

QUESTION:

I am trying to identify a weed that was prevalant where I grew up in North Central Texas. It grows in low spots and along creeks. It has woody stalks with short spines, grows 3'- 6' tall, the leaves are braod and spiny also, and when you break the stalk, it bleeds red sap. It grows in huge clumps and will take over a creek bank.

ANSWER:

The plant that best fits your description is Ambrosia trifida (great ragweed) or, more precisely, Ambrosia trifida var. texana (Texan great ragweed). It grows in waste places and, although native, it is considered invasive in some areas. One of its common names is blood ragweed and the description in Shinners & Mahler's Illustrated Flora of North Central Texas, p. 310, for Ambrosia trifida L. var. texana reads:

"...sap blood red.. . The sap stains the hands red if the tissues are damaged."

Here are additional photos of Ambrosia trifida (giant ragweed) from the University of Texas "Image Archive of Central Texas Plants" and still more photos from the Freckmann Herbarium, Universtiy of Wisconsin.


Ambrosia trifida var. texana

Ambrosia trifida var. texana

Ambrosia trifida var. texana

 

 

More Plant Identification Questions

Identity of plant in Kentucky with fuzzy grayish-green leaves
September 03, 2012 - I would like to know about a plant that I do not know what it is. I had this plant just come up in my flowerbed, that looked like a tobacco plant but the leaves looked like a lambs ear plant. It was ...
view the full question and answer

Plant identification of Indian Cane
June 18, 2011 - I live in southern Alabama. We have a plant that is wild but I can not find any info on it. My grandmother called it Indian Cane. The stems are red and you can chew them, they have a sour taste
view the full question and answer

Will Butterfly Plant Survive in Mansfield, Texas
January 06, 2012 - I have a butterfly plant that was very successful (about 4 feet tall) right up until the cold snap three weeks ago. I've read they have a tap root, so I'm hoping it will come back next spring. Mea...
view the full question and answer

Identification of tree blooming in Austin with yellow balls
March 21, 2012 - What is the tree/large shrub that is blooming now (mid-March) in the Austin area? It has small mesquite-type leaves, round yellow balls with fuzz on them and is fragrant. Thanks!
view the full question and answer

Plant identfication
April 06, 2009 - slow growing woody vine, yellow flowers, (grows butterfly shape leaves with seed in middle of it) in addition to the regular leaves.
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