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
1 rating

Tuesday - May 29, 2012

From: Alton, VA
Region: Mid-Atlantic
Topic: General Botany, Poisonous Plants
Title: Can foxglove poison be transmitted to the soil and taken up by another plant
Answered by: Nan Hampton


Hi Mr. Smarty Plants, Recently I discovered a Foxglove that had come up after being planted 2 or 3 yrs ago. Next to it I have some medicinal Feverfew growing. (They were so close together I suspect they were sharing root space.) Is it possible for the Foxglove to have passed its poisons on my Feverfew? If there is a remote possibility I will pull up the Feverfew, to ensure our safety. Thanks for your time in answering.


Mr. Smarty Plants assumes you mean Digitalis purpurea (purple foxglove), a native of Europe, which is highly toxic.  However, if you mean Penstemon cobaea (Wild foxglove) or Penstemon digitalis (Foxglove beardtongue), they are not on any toxic plant list that I have checked.  There are several species of Agalinis that are called "false foxglove" and none of these appears on any of the toxic plant databases either.  Any Penstemon or the Agalinis would be fine growing with your feverfew.

There are plants that produce chemicals that can affect other plants, either beneficially or harmfully.   This is called allelopathy and, generally, the effect is associated with competition between plants and inhibiting the growth of other plants. The allelopathic chemicals may affect the target plant by leaching into the soil from fallen leaves or fruit or they may be exuded by the plants' roots. The classic example is the allelopathic effect of walnuts which were known as early as Roman times to kill or otherwise inhibit the growth of other plants near them.  Not all plants release chemicals into the soil and I could find no evidence that Digitalis purpurea does.  Plants certainly take up mineral and chemical compounds from the soil where they grow and are known to take up toxic substances such as lead, arsenic and mercury.  However, I can't really find evidence that a plant such as Digitalis purpurea exudes any of its toxins into the soil and, if it does, that Tanacetum parthenium (Feverfew) would be capable of taking up enough of the toxin to be harmful.  You might feel safer about using the feverfew, however, if you moved it to another spot in your garden and leave the purple foxglove growing where it is.



More Poisonous Plants Questions

Native plants toxic to horses
March 09, 2007 - I would like to landscape with native plants (I live south of you in Harlingen, TX) but I am concerned some might be dangerous to my horses. Do you have a list of either safe native plants or native ...
view the full question and answer

Is non-native Tillandsia air plant poisonous to cats?
June 07, 2010 - Are Tillandsia/air plants poisonous to cats? Please help!
view the full question and answer

Is cat palm (Chamaedorea cataractarum) poisonous?
March 18, 2009 - I have a Cataractarum (Cat) Palm and am wondering if it is poisonous. I have a Cockatiel who likes to play in it. Thank you!
view the full question and answer

Non-native Star Jasmine poisonous to dogs from Dallas
May 20, 2013 - Is star jasmine poisonous to dogs?
view the full question and answer

Palm tip wound in Sacramento CA
June 25, 2009 - My husband was stuck in his calf with a palm leaf, he is now complaining of stiffness where it went in, is there any kind of poison in it?
view the full question and answer

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