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
1 rating

Wednesday - August 19, 2009

From: San Marcos, TX
Region: Southwest
Topic: Poisonous Plants
Title: Toxicity of Yucca leaves San Marcos, TX
Answered by: Amy Johnson


Can you tell me if Yucca constricta leaves are poisonous? I ran into one at night and the next morning had a hive-like, VERY itchy rash.


The roots, at least, of Yucca constricta (Buckley's yucca) do contain saponins, which, while toxic to humans, are usually poorly absorbed and therefore do not usually irritate unless you are sensitive or allergic to them.  Incidentally, beneficial uses of these same saponins have been found for humans as well, usually involving cooking them to remove any toxicity.  You mentioned the leaves, and it is possible that some of the sap containing saponins from the plant could have escaped upon contact and caused the intense irritation in your skin, especially if you are sensitive or allergic to it.  It's also possible that there was more than just the Yucca itself involved - other pollen or bacteria could have been on the leaf or even your skin to begin with, and the abrasion caused by contact may have allowed one of those to penetrate and therefore irritate the surrounding skin.  Hopefully your rash is healing now - such a rash sounds very yucca!

Yucca constricta

Yucca constricta

Yucca constricta



More Poisonous Plants Questions

Alpacas poisoned in pasture in Texas
October 26, 2008 - Two of my alpacas were poisoned by something growing in two of my pastures. One of the suspects is cussus trifoliata, aka, cow itch vine, sorrelvine. I have searched diligently and can find no refere...
view the full question and answer

Wild plums for jelly from Conroe TX
December 18, 2012 - Do wild plum trees grow in my area? I want to get some next summer to make plum jelly.
view the full question and answer

Mulberry sap in the bloodstream from Kansas City
November 13, 2010 - What affect does mulberry sap have if put in contact with the blood stream?
view the full question and answer

Flying insects eating leaves of non-native Brugmansia in Aline CA
October 17, 2013 - I have an Angel Trumpet tree. We live in Aline, California 30 miles east of San Diego. Little yellow and black flying bugs eat the leaves. Do you have a remedy for this problem.
view the full question and answer

Is Artemesia ludoviciana allelopathic?
February 20, 2009 - I recently read that Artemisia ludoviciana is allelopathic to some other plants. I planted some last fall between a rusty blackhaw viburnum and a Mexican buckeye. Do you know whether it is phytotoxi...
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