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?

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
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
1 rating

Wednesday - May 06, 2009

From: San Antonio, TX
Region: Southwest
Topic: Non-Natives, Diseases and Disorders, Trees
Title: Will Mountain Laurels be harmed by juglones from my pecan tree?
Answered by: Jimmy Mills

QUESTION:

Hi. I just bought a house. It has a big pecan tree at the edge of the front lawn next to the street. I guess it's about 25 feet from the front of the house. I was thinking of planting mountain laurels near my front windows, pretty far from the pecans, but I read on another forum that mountain laurels will not grow within 50 feet of a walnut tree. Doesn't the pecan have the same toxin as the walnut, and so would it be a bad idea to try mountain laurels in my spot? If not, what about loquats?

ANSWER:

The pecan Carya illinoinensis (pecan) is a member of the family Juglandaceae which contains the Hickories and Walnuts. Members of the family produce the chemcal juglone that is allelopathic  to some plants but not others. One role of the toxin is to prevent the growth of competing plants under the tree. It appears that the level of  juglone in pecans is less than in walnuts. 

You can see lists of plants susceptible to juglones and those tolerant of juglones from Michigan State University and Ohio State Univeristy. Mountain Laurel Kalmia latifolia (mountain laurel) appears on the susceptible list, but this is probably not the Mountain Laurel you have in mind (it doesn't usually grow in Texas). In San Antonio, Mr. Smarty Plants suspects that you want to plant Sophora secundiflora (Texas mountain-laurel) which is not on the susceptiple list, and would be a great addition to your front yard.

As for loquats; since the mission of the Ladybird Johnson Wildflower Center is to increase the sustainable use and conservation of native wildflowers, plants and landscapes, Mr Smarty Plants would prefer that you not plant loquats which have been introduced from Southeastern Asia.


Carya illinoinensis

Sophora secundiflora

Kalmia latifolia

 

 

 

 

 

 

 

 

 

 

More Non-Natives Questions

Help for a Transplanted Bougainvillea
April 22, 2014 - I recently planted a bougainvillea in our south-facing front yard. While planting it, we inadvertently severed a large portion of the root system from the plant. What, if anything, can we do to help...
view the full question and answer

Identifying problem with non-native plumbagos in San Antonio
November 21, 2009 - Barbara Medford answered my question on plumbagos..we have the ones that grow crazy in TX (not sure which species, but w/ the bright blue/purple blooms..). I have pictures and wasn't sure where to se...
view the full question and answer

Non-native gardenia in Cedar Park, TX
October 07, 2009 - My gardenia, which is planted in a large pot, drops the buds before they bloom. What do I need to do. I already fertilize it with gardenia food.
view the full question and answer

Care of non-native, hybrid petunias
August 31, 2004 - I have a beautiful Petunia Tiny Tunia Violet plant which has been flowering nicely (in sun and shade environment). Suddenly, a few days ago, it began to look like it's dying--stalks all dried out. Is...
view the full question and answer

Consumption of carbon dioxide from South Korea
December 07, 2011 - I am curious about what flowers consume CO2 for growing (especially 1-year life flower). Thanks.
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 | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center