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
1 rating

Thursday - October 04, 2012

From: Lansing, MI
Region: Midwest
Topic: Planting, Trees
Title: Native plants for under a black walnut from Lansing MI
Answered by: Anne Bossart

QUESTION:

What native plants can you recommend that will grow in Michigan under a mature black walnut tree?

ANSWER:

Walnut trees can present a real challenge for gardeners.  Although they are great shade trees, they exude a chemical called juglone which inhibits the growth of other plants near it.  A great adaptation if you are a walnut tree and want lots of room to grow; not so great if you are a gardener with a limited amount of space!

Research indicates that the juglone increases the alkalinity of the soil, creating harsher conditions for plants nearby (the ideal condition for most plants is neutral to slightly acidic soil) so the pH of your soil will impact your success.  Also, if your soil is sandy and well drained, the effect of juglone may be less than if you have clay soil. There are publications which you will find by doing an internet search like this one by Virginia Cooperative Extension service which will be helpful.  Although not Michigan specific, Walnuts behave in a smiliar way across their native range.

Although our Native Plant Database can create lists of plants native to Michigan using the Combination Search it cannot sort according to tolerance to juglone.  However, many of the individual plant entries do indicate if a plant is juglone tolerant.  So in your search for native plants that are tolerant, you will have to check a few lists of plants like this one from Grandville, Michigan which lists non-native plants as well as native and this one from a native plant grower in Ontario (with many native plants in common with Michigan).  You can cross reference those suggestions against our lists of native plants. Many Extension offices do publish fact sheets and sometimes will have one with suggestions so do call or visit yours, but often a gardener is left to trial and error. 

Unfortunately, we can't just give you a list because every situation is different so finding suitable plants is a bit of an arduous process.

 

More Trees Questions

Plants for under live oak in Houston
July 09, 2011 - Hi, We have a live oak in our back garden in Houston and would like to plant a combination of some native shrubs and flowers near it (preferably perennial). The garden bed is about 4 metres from the...
view the full question and answer

Planting ornamental cherries in GA
February 18, 2011 - What is the correct way to plant ornamental cherry trees in N. Georgia Mountain clay soil? Which is the hardiest variety?
view the full question and answer

Evergreen for privacy in PA
July 18, 2011 - We need to plant a privacy/sound barrier hedge/hedgerow and my husband says it must be evergreen. I am not familiar with which species would be native to our area and I just don't trust those big sto...
view the full question and answer

Looking for a specimen shade tree in San Rafael, CA
June 04, 2013 - I'm looking for a specimen shade tree that can get 30'x30', that doesn't drop a bunch of crud (seeds, etc) on the patio (leaves are ok), medium to low water requirement, roots are behaved, zone 9,...
view the full question and answer

Failure to thrive of Magnolia grandiflora in Las Vegas NV
January 17, 2011 - I live in Las Vegas, NV and have several Magnolia Grandiflora trees. They were doing well until 2 years ago when they started losing their leaves. The leaves turn brown or very dark on the edges. One ...
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