Host an Event Volunteer Join Tickets

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 - May 01, 2014

From: Houston, TX
Region: Southwest
Topic: Non-Natives, Diseases and Disorders, Pests, Transplants, Shrubs
Title: Problems with non-native Banana Shrub from Houston
Answered by: Barbara Medford

QUESTION:

My 7' beloved Banana Shrub (magnolia) has white dots on top of the leaves and nasty black stuff covering the backside of the leaves. The plant is dropping leaves. What can I do to save it? I has been in a big pot for 13 years and when I saw the white spots and black nasty stuff last week, I transplanted the root bound tree into the ground where it will get more sun. I pulled open the roots and cut them as best I could. I have been spraying and wiping the leaves, top and bottom with Palmolive dish soap in water for three days now. But the tree looks very sick. Please, please help. Madalene Hill of Festival Hill in roung Top gave me this tree 13 years ago so it is very dear to me.

ANSWER:

We were very confused when you referred to your plant as a Banana Shrub (magnolia). Here is information we got from Wikipedia:

"Magnolia figo (also called Banana Shrub, Port Wine Magnolia, Michelia figo) is an evergreen tree growing to 3-4 m tall. It is native to China. Susceptible to black soot."

The Lady Bird Johnson Wildflower Center is dedicated to the growth, protection and propagation of plants native not only to North America but also to the area in which those plants are being grown; in your case, Harris Co., TX. That is what confused us, we knew that Banana Shrub was not in our Native Plant Database but magnolias are native to North America and, in fact, Magnolia grandiflora (Southern magnolia), is native to Harris County.

Magnolia figo, alas, is not, but is native to China. This puts it out of our area of expertise; however, we might be able to make a couple of suggestions as to what is wrong. The first thing that comes to mind is aphids - they are small white bugs, and deposit aphid poop on the bottom side of leaves of affected plants, which then turns a moldy black. Check out this article from the University of California Integrated Pest Management on what that pest looks like and how to deal with it. The article from Wikipedia also mentioned "Susceptible to black soot." When we searched the Internet on "black soot plant disease" we got this article from Gardening Know How on Sooty Mold. When we read that article it sounded a whole lot like aphids, again, were causing the problem. Hopefully, from one or the other you will get help for your plant.

 

More Non-Natives Questions

Dying non-native red tip photinias in Lexington NC
June 27, 2009 - Large Red Tip bushes, what can I do to keep them alive? I have a few and they are dying. What can I do to save them?
view the full question and answer

Ridding non-native centipede grass of native rattlesnake weed in Myrtle Beach SC
April 25, 2010 - How do I get rid of "rattlesnake weed" in my lawn of centipede grass in Myrtle Beach SC?
view the full question and answer

Survival of non-native mimosa in Pennsylvania
June 08, 2008 - Can a mimosa tree survive in Pennsylvania weather?
view the full question and answer

Care of non-native lilac
July 14, 2006 - How and when do we prune lilacs bushes ?
view the full question and answer

Invasive plants in native plant area from Austin
May 15, 2012 - Why do invasive plants grow in native plant territory?
view the full question and answer

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