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

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 Shrubs Questions

Winter-interest plants in Wynnewood PA
July 11, 2010 - Could you please suggest flowering plants that provide winter interest after drying out (ie with seed pods or interesting dried flower heads)? I'm looking for something that grows in full sun. Thank ...
view the full question and answer

Poison Ivy in Semi-wetland Massachusetts
June 27, 2013 - You answered this question for Tennessee, but I would like an answer for a Massachusetts semi-wetlands area: What can I plant to discourage poison ivy, or at least make it very clear that it is poison...
view the full question and answer

Climbing Roses for the Pacific Northwest
January 23, 2016 - I'm trying to find out which types of climbing roses may exist in the Pacific Northwest. I live in western Washington, and I have a small yard with several large hedges bordering it. I'm growing hai...
view the full question and answer

Privacy Screening Plant for New York Narrow Site
April 20, 2013 - I need privacy screening on the side of my house in Mount Kisco, New York located 40 miles north of New York City. The area gets plenty of sun but is somewhat narrow. What evergreen bushes or trees ...
view the full question and answer

Erosion Control for a NC Clay Slope
June 06, 2013 - Hi, We have a large slope on the road edge of our property that has been gradually eroding with spring rains (NC red clay). We would really like to plant something for erosion control but the bank is...
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