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

Sunday - August 01, 2010

From: Mt Pleasant, MI
Region: Midwest
Topic: Shrubs
Title: Dogwood under a black walnut in Mt.Pleasant MI
Answered by: Barbara Medford

QUESTION:

Can I grow red or yellow twigged dogwood near a black walnut?

ANSWER:

You can plant a Cornus sericea (redosier dogwood) anywhere you choose; whether it will thrive or even live more than a year or so under a Juglans nigra (black walnut) is another question entirely. Both are native or near your area of Isabella County, in central Michigan, USDA Hardiness Zones 4a to 5a.

The problem, as you may know, is a characteristic of black walnut to emit juglones, substances intended to discourage or prohibit competition from other plants. We found an excellent article from  Virginia Cooperative Extension Black Walnut and Allelopathy which fully explains this procedure. Even plants some distance away can be affected because every part of the tree exudes the juglones, including roots which may extend 3 times the size of the crown. However, this same article had a chart of plants that were resistant to the effects of allelopathy, including trees and shrubs. On this chart of resistant plants "dogwood, flowering" was listed. There are 14 members of the genus cornus, dogwood, native to North America, and all of them appear to us to be flowering including Cornus sericea (redosier dogwood).

Therefore, we are assuming that it would indeed be okay to plant the dogwood in the area of the black walnut. If the dogwood does fail to thrive, you can always blame moles or bugs or too much rain or too little rain, just don't blame the researchers or Mr. Smarty Plants. 

From the Native Plant Image Gallery:


Cornus sericea

Cornus sericea

Juglans nigra

Juglans nigra

 

 

 

More Shrubs Questions

Propagation of wax myrtle from Lafayette LA
December 10, 2012 - Hello, I have a good portion of Wax Myrtle Seeds. How do I get them Started for planting? Have been told to put several seeds in a Jar lid in a very damp paper-towel & leave them there till they ...
view the full question and answer

Annabelle hydrangeas blossoms drooping to ground in Wilmette, IL
April 10, 2011 - I have a row of Annabelle Hydrangeas that become very heavy and droop over the entire width of the bed. I would like to know what I can use for support so that they will stand up and allow me to plan...
view the full question and answer

Purple sage with black residue on leaves in Georgetown TX
October 02, 2009 - I have 2 very healthy tx. purple sage that have developed a black residue on some leaves, and is a "sticky" substance..any ideas what this is and how to treat???
view the full question and answer

need recommendation for small evergreen shrub in Katy, TX
September 14, 2015 - recommendation regarding small to mediun evergreen palnt in full sun in 2feet by8 feet area.
view the full question and answer

Decline ot Heartleaf rosemallow from Austin
March 26, 2012 - My tulipan del monte -a new small plant from the wildflower center--did great all winter and was forming a new flower bud, just died in a matter of a few days. It looks like it "dried up", no visib...
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