Contact Us Host an Event Volunteer Join

Support the plant database you love!

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 Planting Questions

Repotting non-native Agave ghiesbreghtii from Spring TX
June 03, 2012 - I've recently purchased an Agave ghiesbreghtii, and will need to re-pot it soon. I have some cactus soil mix as well as a few rocks to put in the bottom of its new pot. There seem to be roots comi...
view the full question and answer

White fuzz on pine tree bark in Dartmouth MA
July 13, 2010 - We have white fuzz on our pine tree bark?
view the full question and answer

Flowers to bloom in next 4 months from Aransas Pass, TX
July 24, 2013 - Looking for seeds to put down that will bloom over the next 4 months or so in the southern gulf coast area
view the full question and answer

Plants under oak trees
April 21, 2009 - I have a large live oak (actually several) in my front yard, which basically puts the beds at the foundation of my house in full shade. I tore out the builder-boxwoods and privets, hoping to plant so...
view the full question and answer

Butterfly plants from Austin TX
December 17, 2012 - I have a butterfly garden in the front part of the house facing the south side. However it is also mostly under a few Oak trees that cast shadow over half of the front yard starting early afternoon. ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.