Explore Plants
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.
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
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.
More Plant Identification Questions
Smarty Plants on forbs
October 16, 2005 - What kind of plant is a forb? I see the term used frequently in reference to grasses (I think), but I can't figure out exactly what a forb is.
view the full question and answer
Plant that smells like cinnamon in Milford OH
June 07, 2010 - Wanting to know what wildflower/weed would be so aromatic and smells like cinnamon? Always enjoy this wonderful smell when my husband and I ride the motorcycle, but don't know what it is. Would like ...
view the full question and answer
What is sage-like plant in New River AZ?
July 17, 2009 - I have a sage like looking plant growing wild in my yard. I live in the Sonora Desert. Its leaves are purple and once a year in spring it will bloom small blooms that are lavender. It grows 2 to 3 an...
view the full question and answer
Nomenclatural puzzles
March 25, 2008 - Hi Mr. Smarty Plants. I have been looking all day for this information. I am look for a plant that is in the genus Cucumis but not in the family Cucurbitacea. A plant that is in the family Cucurbit...
view the full question and answer
Tall skinny plant with tubelike flowers
May 14, 2008 - I already posted a question regarding a skinny plant with tiny tube like flowers and you gave me 6 possibilities unfortunately it is not one of them. I happened to see the plant again in my neighborh...
view the full question and answer
 |
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. |
