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?

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
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

QUESTION:

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.

ANSWER:

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

Propagation of Pacific dogwood
November 21, 2015 - When do I plant Pacific dogwood seeds? How deep and far apart should they be planted? The elevation will be around 5k.
view the full question and answer

Plant ID in Flower Mound TX
June 23, 2009 - I have a large native tree in the back yard, leaves resembles a live oak, but evergreen,& small white flowers in the spring, very tall vase shaped tree. It had no acorns or berries.
view the full question and answer

Distance from existing structures for live oak
April 18, 2009 - How close to your house slab, driveway and footpaths should you plant live oaks so as to avoid in the future damage from roots, falling branches, etc?
view the full question and answer

Recently planted Chinquapin Oak with browning leaves in Marlin, TX.
July 31, 2012 - We planted a Chinquapin Oak this in March 2012. As of July 21, 2012, the tips of the leaves on the lower branches are turning brown. We cannot see any insects. There does not appear to be any fungu...
view the full question and answer

Cedar Elm trees for Rockport, TX
January 08, 2010 - Cedar Elm trees for the Gulf Coast area? I live alongside a fresh water lake with sandy soil that is 2 miles from the bays. Along the shoreline, I'd like to replace a Weeping Willow that is in decl...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center