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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

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

Removing Mountain Laurel Seed Pods from Austin
August 14, 2012 - Is it best to remove seed pods from Mt. Laurel or leave them on the tree?
view the full question and answer

Plants in wheelbarrow dying in Jacksonville, FL
June 22, 2011 - I planted a wheelbarrow with daisies, petunias and black and blue salvia. the salvia is thriving, but the others died. Is the salvia toxic to them?
view the full question and answer

Identity of poisonous thorn bush in Montgomery Texas
May 29, 2012 - What is the name of a poisonous thorn bush in Montgomery Texas?
view the full question and answer

Will Hellebores planted in the soil near vegetables transfer poisons to them?
April 29, 2015 - I just planted helleborus in my garden and have now read that they are toxic. They are planted near vegetable plants, will they affect the vegetables and leave them inedible? Also, are they toxic to d...
view the full question and answer

Evergreen pet-safe shrubs for house and screening in McKinney TX
April 15, 2010 - Looking for shrub, preferably evergreen, to plant near the house that can handle wet ground and is pet (dog, cat, horse) safe. The area became boggy after we had an underground water leak that is now ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center