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?


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

Removing poison ivy in Cuba MO
August 27, 2011 - I bought a home with a huge bed of hybrid iris but the bed is thick with poison ivy. If I cover myself head to toe to prevent getting it is there a way to clean the tubers so they will not be poison? ...
view the full question and answer

How toxic are milkweed (Asclepias spp.)?
November 01, 2011 - We are considering a monarch waystation for our local elementary and are concerned about milkweed toxicity. Would it be safe to plant it in reach of children?
view the full question and answer

Plant for privacy hedge in Oklahoma that is not poisonous to dogs
April 01, 2012 - Hello! I am looking to put a privacy hedge fence in my yard. I love the look of American Holly, however, I have a dog who eats everything so I worry that this will not be a wise choice with the b...
view the full question and answer

Are berries from the Carrot Wood Tree toxic to animals?
May 26, 2009 - Hello, I am trying to find out if the berries on the carrot wood tree are toxic to animals - dog?
view the full question and answer

Is resurrection plant (Selaginella lepidophylla) toxic?
February 14, 2009 - Is Resurrection plant (Selaginella lepidophylla)toxic? Is it safe for children to handle?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2015 Lady Bird Johnson Wildflower Center