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
Not Yet Rated

Tuesday - September 02, 2008

From: San Antonio, TX
Region: Southwest
Topic: Poisonous Plants
Title: Curing plant rash
Answered by: Joe Marcus


I went walking in the woods a few weeks ago, and my leg swiped some kind of cactus or something. It scratched me up and I had to remove little white spines with tweezers. I developed an intensely itchy rash that three weeks later is just as bad as when it first happened. It is not poison ivy or anything.. I have no idea what it is and it is not getting any better. I tried using Tea Tree oil and Shea oil.. it helps a little but has not cured the problem. I don't want to take any pharmaceutical drugs. Do you know how I can resolve this naturally?


We don't think we can answer your question since giving medical advice is not really in our province, but it seems that after three weeks you might want to consult with a medical doctor.  However, we may be able to help you identify the cause.  If the offending plant was a cactus, it was likely Cylindropuntia leptocaulis (Christmas cactus), also known as Pencil cactus or Tasajillo.  Other possible offenders include Urtica chamaedryoides (heartleaf nettle), Cnidoscolus texanus (Texas bullnettle), and Tragia spp, (Noseburn). A less likely candidate (because it's not native to that area but occurs not too far away) is Cevallia sinuata (stinging serpent),  Finally, any number of insects with stining hairs, including saddleback caterpillars and stinging asps may have assaulted you.


From the Image Gallery

Texas bullnettle
Cnidoscolus texanus

Branched noseburn
Tragia ramosa

Stinging serpent
Cevallia sinuata

Cylindropuntia leptocaulis

Betonyleaf noseburn
Tragia betonicifolia

More Poisonous Plants Questions

Using cattail fluff to stuff pillows
April 22, 2007 - Me and my children filled a pillow case with cattail feathers today and brought it home. My mother says that it is going to get or attract bugs. Are there any dangers in this little project? Than...
view the full question and answer

Wildlife garden for Austin
May 19, 2013 - I am trying to make my backyard more wildlife friendly. I have pecan trees for the canopy and some understory shrub/trees like rough leaf dogwood and redbud. I am having a really hard time finding sui...
view the full question and answer

Is Desert willow poisonous to horses in Boerne TX
July 17, 2009 - I have just purchased Bubba Desert Willows and have horses. Will they eat them, do you know and if so will they be harmed? Thanks
view the full question and answer

Vine non-toxic to alpacas and dogs from Fowler CA
June 29, 2012 - We have alpacas and would like to plant a flowering vine on a backyard fence that adjoins the pasture. We live in Central California so we have many hot days during the summer and would like a plan...
view the full question and answer

Want a vine, non-toxic to dogs, for Reno, NV.
September 11, 2012 - I want a non toxic (to dogs) vine for Reno, NV
view the full question and answer

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