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
3 ratings

Wednesday - April 14, 2010

From: Valley Center, CA
Region: California
Topic: Propagation
Title: Plants that will grow under a magnolia tree.
Answered by: Nan Hampton

QUESTION:

We live in California near San Diego and have a Magnolia Tree. We have tried to plant many types of flowers around the tree only to have them die. Is there a particular type of plant that we should be planting?

ANSWER:

You have discovered for yourself that magnolias are allelopathic to other plants.  This means that the magnolia produces chemicals that inhibit the germination of seeds and growth of plants that are potential competitors for its resources.  The roots and fallen debris (leaves, flowers, etc.) from the magnolia tree contain substances that limit the growth of other competing species that grow underneath it. In the case of magnolias, the substances are sesquiterpene lactones—costunolide and parthenolide—(see Abdelgalel, A. M. and F. Hasinaga.  2007. "Allelopathic potential of two sesquiterpene lactones from Magnolia grandiflora L." Biochemical Systematics and Ecology Vol. 35, no. 11, pp. 737-742.)  A complicating factor is that many plants won't grow in the dense shade created by the magnolia tree—or any other tree, for that matter.

Walnuts trees (Juglans sp.) also have allelopathic effects on plants growing beneath them.  The substance produced by walnuts is called juglone.  Virginia Cooperative Extension has an article "Trees for Problem Landscape Sites -- The Walnut Tree: Allelopathic Effects and Tolerant Plants" that offers some tips on reducing the effects of juglone on plants growing near walnut trees that could apply to your magnolia.  One important tip is to "Regularly clean up all fallen leaves and fruit..., keeping debris away from desired landscape plants."  They also list plants that are tolerant to juglone.  These, of course, are NOT guaranteed to be tolerant to the sesquiterpene lactones in magnolias, nor are they necessarily native to Southern California (nor, for that matter, are any of the Magnolia species). 

I could find no list of plants that are resistant to the allelopathic effects of magnolias.  So, my recommendations to you are:  1) keep the debris from the magnolia cleaned up from the area where you want the flowers/plants to grow, and 2) choose native plants that are shade-tolerant.   Here are a few recommended shade-tolerant herbaceous plants that are native to San Diego County or an adjacent California county:

Apocynum androsaemifolium (spreading dogbane)

Argentina anserina (silverweed cinquefoil)

Athyrium filix-femina (common ladyfern)

Claytonia perfoliata (miner's lettuce)

Fragaria vesca (woodland strawberry)

Lobelia cardinalis (cardinalflower)

Maianthemum stellatum (starry false lily of the valley)

Polystichum munitum (western swordfern)

Pteridium aquilinum (western brackenfern)

Viola adunca (hookedspur violet)


Apocynum androsaemifolium

Argentina anserina

Athyrium filix-femina

Claytonia perfoliata

Fragaria vesca

Lobelia cardinalis

Maianthemum stellatum

Polystichum munitum

Pteridium aquilinum

Viola adunca

 

 

 

 

 

More Propagation Questions

Dividing obedient plant in New Waterford OH
September 19, 2009 - I live in northeast Ohio, and have an obedient plant, which has spread, (a little) since last year when I bought it. I really do like the plant, and wanted to put it in several more areas in the garde...
view the full question and answer

Propagating Eustoma exaltatum from seed in Lucas TX
September 27, 2010 - Hello I know that Texas bluebells Eustoma exaltatum ssp. russellianum are supposed to be difficult to start from seed. Does Mr. Smarty Plants have any helpful hints? Thanks!
view the full question and answer

200 year old white oak with no acorns in Oregon City OR
April 26, 2010 - We have a white oak tree in our yard that is about 200 yrs old. We have lived in the house for 30+ years, and have never seen an acorn. We have had it pruned by an arborist, who said it is in good...
view the full question and answer

Vehicle friendly oak trees for Austin
March 30, 2008 - Do Chinquapins, Shumards or Live Oaks produce lots of tree sap? I'm looking for a vehicle friendly Oak tree to be installed in parking areas in Austin, Texas.
view the full question and answer

Planting begonias in the Dallas area
March 25, 2009 - What month is it time to plant begonias in the Dallas, Texas area?
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