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
Not Yet Rated

Sunday - March 24, 2013

From: Dallas, TX
Region: Southwest
Topic: Compost and Mulch, Diseases and Disorders, Trees
Title: Allelopathy of American elms from Dallas
Answered by: Barbara Medford

QUESTION:

Are American elms at all allelopathic?

ANSWER:

There are four members of the genus Ulmus (elm) native to Texas and in or near Dallas County:

Ulmus alata (Winged elm)

Ulmus americana (American elm)

Ulmus crassifolia (Cedar elm)

Ulmus rubra (Slippery elm)

Black walnut isn't the only tree that produces juglone. This chemical is also secreted in smaller amounts by English walnut, hickory and pecan trees.Other trees with allelopathic properties include tree-of-heaven, sugar maple, hackberry, American sycamore, American elm, southern wax myrtle, cottonwood, black cherry, sassafras, red oak and black locust.

Certainly, in our experience, members of the Juglandaceae family (most familiar - walnuts, pecans) are the most prominent examples of allelopathy, but the American elm is definitely included as being able to deal with competing plants with chemicals. Please note that it is difficult to impossible to grow anything under any tree, including grass, because of the needs of the tree roots for moisture and nutrients from the soil and because of the shade from the tree. Here in Texas, we would vote for the trees and spread mulch under the shade of the tree. See our How-To Article Under Cover with Mulch.

 

From the Image Gallery


Winged elm
Ulmus alata

American elm
Ulmus americana

Cedar elm
Ulmus crassifolia

Slippery elm
Ulmus rubra

More Compost and Mulch Questions

Turf grasses and alternatives for NH
October 23, 2010 - I live in Hancock, NH, just north of Peterborough. We just bought a relatively new house that pretty-much has no lawn and minimal landscaping. Can you (or anyone) suggest native lawn grass alternati...
view the full question and answer

Planters for wildflower exhibit in Jemez Springs NM
November 28, 2010 - I am planning to have a wildflower/pollinator exhibit at a visitor center located on a high elevation grassland (no trees). I would like advice on the size of the planter boxes.The area is located at...
view the full question and answer

How to make a lawn into a prairie in Arlington, Texas
September 15, 2010 - I am removing lawn grasses in order to start a native prairie meadow. After grass removal, I'll put down 1/2" of compost. I will broadcast wildflower seeds on the compost. If I mulch after broadcas...
view the full question and answer

Interaction of Habiturf and St. Augustine grasses from Willow City TX
April 16, 2012 - How does Habiturf and St. Augustine interact? Does one dominate the other? Can you plant them in close areas? Thank you.
view the full question and answer

Advisability of landscape cloth in native gardens
July 18, 2007 - Is the use of landscape cloth healthy or unhealthy in native gardens?
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 | STAFF
© 2015 Lady Bird Johnson Wildflower Center