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

Friday - July 08, 2011

From: Vista, CA
Region: California
Topic: Poisonous Plants, Trees
Title: Are palm tree seeds toxic?
Answered by: Nan Hampton


Are palm tree seeds toxic to other plants? I have palm trees around my pool and it seems that nothing will grow very good where the old seeds are in the ground.


I'm not sure what palms you have.  The only palm native to California is Washingtonia filifera (California fan palm), but there are other palms commonly found there [e.g., Phoenix canariensis (Canary Island Palm) from the Canary Islands, Phoenix dactylifera (Date palm) from Asia and Washingtonia robusta (Mexican palm fan)].

I searched for references to palms and allelopathy and below are the only references I found. 

M. I. Khan in an article, [Allelopathic potential of dry fruits of Washingtonia filifera: Inhibition of seed germination.  Physiologia Plantarum, 54(3):323-328, 1982] says that the leachates of the fruits of this palm inhibited the germination of the seeds of lettuce and cucumbers.

Another article by Khan [Allelopathic potential of dry fruits of Washingtonia filifera (L. LINDEN) H. WENDL.  II.  Inhibition of seedling growth.  Biologia Plantarum, 24(4), 1982] reports the allelopathic effect of the dry palm fruits on growth of the seedlings of lettuce, red cabbage, tomato and cucumber.

Finally, A. K. Mukherjee [Allelopathy in Phoenix paludosa pure stand formation.  Journal of Economic and Taxonomic Botany, 12(2), 1988] reported that the roots of Pheonix paludosa (Mangrove date palm), an Asian species related to date palms found in California, delayed germination and retarded the growth of gram (a kind of bean) seed.   Mukherjee speculates that a growth retardant from the roots of the palm eliminates competing plants and results in pure stands of the palm in India.

These references are to experiments performed 20 years or more ago and no one has repeated them, as far as I know, nor has anyone reported allelopathy associated with any other palm trees.  That doesn't mean that your palm seeds or fruits don't have any allelopathic properties.  Since palms are prevalent in lots or landscapes, however, it seems that it would be reported by homeowners and landscapers.  

Just in case the seeds or any other parts of the above ground tree is inhibiting the growth of plants underneath your palm, you can alleviate the effect by keeping the area under and around the tree free of fruits, seeds and fronds.  Also, since the palm is going to provide a good deal of shade, this could be part of your problem.  Try choosing shade-loving plants for the area under the palms. 


More Trees Questions

Male and female Ilex decidua ( Possumhaw) trees
May 18, 2015 - I was excited to finally find and purchase a male and female possum haw pair via Amazon. (Berry Poppins variety). They were marked male-female and are thriving. But the male has little flowers and the...
view the full question and answer

Difficulty with Clay Soil from Palm Bay, FL
August 22, 2012 - I had a very nice little native shady area behind my house for over 40 years, but now it has been cleared except for a 100 foot tall live oak in the center of this raised mound (50' x 80'). I've be...
view the full question and answer

Watering a Montezuma Cypress in Spring Branch, TX
July 11, 2013 - Live near San Antonio, and have a Montesuma Cypress, 15 ft tall. Great soil. Planted in April, should I keep it moist??? The foliage is getting brown.
view the full question and answer

Junipers for restoring area in Bulverde TX
November 03, 2012 - Are ashe or virginiana junipers for sale around the hill country? I would like to recreate the natural plant life that was bulldozed next to my home. Do you recommend any other types of juniper that ...
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

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