Contact Us Host an Event Volunteer Join

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?

Share

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
2 ratings

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

QUESTION:

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.

ANSWER:

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

Is any part of flowering peach (Prunus persica) toxic to dogs
April 26, 2009 - I know that peach pits and wilting leaves are poisonous to dogs, but can you tell me if any part of the Red Flowering Peach Tree (no fruit) is toxic?
view the full question and answer

Potential allelopathy of cultivar of Artemisia ludoviciana
March 09, 2009 - I recently submitted a question regarding allelopathic potential of artemisia ludoviciana on rusty blackhaw viburnum, not specifying that I meant Vibernum rufidulum. Mr. SP interpreted my viburnum as...
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

Petals of flowers on cake from London
August 28, 2010 - Hi could you please confirm whether it is safe to position an amaryllis on top of a fresh cream cake (it will not be eaten, nor will the stem touch the cream, it will be positioned in a non toxic vial...
view the full question and answer

Shrubs that non-toxic to horses but that they won't eat
October 29, 2011 - I am looking for a low maintenance, low water, green shrub that horses won't eat and will not be toxic to them. I want to hide my neighbors corral and keep down dust on my side. The horses have "l...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.