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 Trees Questions

Problems with non-native citrus trees from Mesa AZ
January 13, 2014 - We have one valencia orange tree and one naval orange tree in our Mesa, AZ yard. Just noticed some oranges on both trees have a 1/4 inch diameter hole through the skin and the orange fruit and skin a...
view the full question and answer

Will desert willow (Chlopsis linearis) grow in N. E. Mississippi
July 21, 2008 - I am located in N.E. Mississippi. A friend of mine sent me a few desert willow seeds. I have about 5 plants growing now that are about 6 inches tall. I was wanting to know first of all, is it possi...
view the full question and answer

Need plants to replace cedars on a 40 degree slope in Boerne, TX.
August 28, 2012 - My backyard is a roughly 40 degree slope that is covered with cedars. The slope is basically all rock, what can I grow here to replace the cedar which drink too much water. I would still like the area...
view the full question and answer

Re-landscaping in Stephenville, TX.
November 17, 2012 - I prefer native plants. We are re-landsacaping, so I need grass, ground cover, vines and flowers to plant in our back yard. We have many trees and the whole yard is shady. A small area might be con...
view the full question and answer

Pfluegerville Screening Hedge
May 25, 2014 - We live just north of Austin in a subdivision built on farm land so we have relatively flat land with good soil. We just put in a pool and are needing a privacy hedge along our 66 ft back fence. We ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center