En EspaÑol

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?


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
3 ratings

Thursday - December 01, 2011

From: Knoxville, TN
Region: Southeast
Topic: Poisonous Plants
Title: North American Plants with Poisonous Thorns
Answered by: Becky Ruppel


Are there any plants in North America that possess poisonous thorns?


In North America there are few plants that have poisonous thorns.  The members of the Solanum (nightshade) genus have thorns and are reported to cause injuries that are slow to heal due to poisonous thorns.  Many members of the nightshade family (Solanaceae) have many poisonous parts (i.e. leaves, stems, fruit, roots, seeds) that cause severe irritation to mammals.  The members of this family are widely distributed across North America. 

Another group of plants that have poisonous “thorns” is Stinging Nettles.  They have tiny hairs on the underside of their leaves that ‘sting’ and cause skin irritation and a burning sensation if they are brushed against. 

Finally, most plants that have thorns can cause mechanical injury, and some injuries result in pieces of the thorn breaking off in the skin.  It would seem as if these plants had poison, but in fact, the swelling and redness around a wound is caused by a foreign object logged in the skin. 

Considering plants outside of North America there are several plants from Africa that have poisonous thorns such as Gymnosporia buxifolia or Dichrostachys spp

I acquired my information about thorny plants from the Botanical Dermatology Database.  There is lots of information there if you would like to read further about the affects of plants with thorns. 


More Poisonous Plants Questions

Controlling Cnidoscolus texanus (Texas bullnettle)
July 18, 2013 - Hello,I need your help to control some nasty weeds in my yard/pasture. I am an old timer and do not have a picture to include—haven't figured out that part of the camera/phone yet. This weed is a pri...
view the full question and answer

Plant with dark black/purple berries in a cluster
November 06, 2012 - Today at our local dog park we noticed a bush/vine that's been growing up the fence is producing berries. It didn't flower at all. The berries look to have started out green and now are changing t...
view the full question and answer

Vines for fence, safe for horses in California
December 12, 2013 - I live in a fire prone part of Orange County, CA named Silverado and own horses. Am interested in fast growing vines to cover a fenced area which are horse safe. Thank you.
view the full question and answer

Smarty Plants on Texas cherry tomato
April 24, 2005 - We just bought 2 Texas cherry tomato plants at the plant sale. We have to container garden in a walled courtyard due to deer. (Would deer be attracted to the plants in a garden with herbs and high de...
view the full question and answer

Allergy-causing plant in the Dallas/Fort Worth metroplex area
March 17, 2011 - Do you know what is growing (or floating in the air) in the DFW metroplex now, but not growing or floating the rest of the year? I have a 3 year old that has gotten extremely itchy this time of the ...
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.
© 2015 Lady Bird Johnson Wildflower Center