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 - November 26, 2013

From: Dripping Springs, TX
Region: Southwest
Topic: Invasive Plants, Non-Natives
Title: Advisability of growing Silybum marianum (Milk thistle)
Answered by: Nan Hampton


I just received a load of clay-mix-dirt - and after our recent rains noticed the pile sprouting what looks like "Milk Thistle." Lots of them. The leaves are spiny and variegated - quite pretty. I was thinking I might translate a few to my native garden but I don't know much about this plant other than it is interesting looking. Would this be a bad idea?


Silybum marianum (Milk thistle) is a native of Southern Europe, the Mediterranean area and North Africa.  As an introduced species to North America it is considered invasive or, at the very least, a noxious weed in many areas.  It is on the Arkansas Noxious Weeds List, the Oregon Noxious Weeds List and the Washington Noxious Weeds List. Here is a link from King County, Washington with information about its bad qualities.   On the other hand, it is also praised for its herbal medicinal properties, but see also the Mayo Clinic reference.  All in all, I would say it would be a pretty bad idea to grow milk thistle.  First of all, it's not native to Texas nor even to North America.  Second of all, it has the potential to be a problem plant if it escapes your flower beds and the seeds can be distributed by the wind.  Why not get seeds of one or more of the Texas thistle species [Cirsium texanum (Texas thistle) or Cirsium horridulum (Yellow thistle)] to grow?


From the Image Gallery

Texas thistle
Cirsium texanum

Yellow thistle
Cirsium horridulum

More Invasive Plants Questions

Controlling vegetation around retention pond in Williamsburg, VA
September 21, 2009 - We planted Juncus effusus around a retention pond and various native shrubs last year. We are having a problem controlling bramble,lespedeza and broadleaf natives from taking over and native trees(wil...
view the full question and answer

Tropical plants for pool landscape in Plano TX
April 05, 2011 - I have a small yard with a pool that I would like to tropically landscape. It faces west (lots of direct sun) and there is about a 3 foot parameter between the fence and the coping. Currently I have...
view the full question and answer

How to eliminate Sawgrass from a small lake in Lindale, TX?
February 23, 2015 - We live on a small acre lake (about 65 acres) and the majority of the lake is surrounded by what the locals are calling saw grass. From the description on the website, I believe they are correct. The...
view the full question and answer

Removal of invasive horsetail in Shelby Township, MI
June 19, 2009 - Please help me or direct me to who may be able to help. I have horsetail (Equisetum) invading my Blue Rug Juniper. Please tell me what I can use to get rid of the horsetail (Equisetum) without killi...
view the full question and answer

Distinguishing wax myrtle from Daphne laureola in Tofino BC
September 02, 2009 - I am wondering how to distinguish California Wax Myrtle from Daphne Laurel, the latter which I would prefer to eradicate from my property. If it is wax myrtle, it gets to live..
view the full question and answer

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