En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
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 Non-Natives Questions

Problems with non-native weeping willow in Villanova PA
July 03, 2009 - My weeping willow (6 years old,80+ft tall),up until this year used to be full and healthy. Last year I trimmed the lower portion of the trunk by cutting off the low hanging branches, but this year so ...
view the full question and answer

Keeping non-native invasive bermudagrass out of yard in Austin
May 30, 2012 - My neighbor just sodded a huge lawn with Bermuda Celebration. I don't want it coming into my St. Augustine. From what I've read on your site and others, I need a deep barrier. Has anyone tried pu...
view the full question and answer

Shriveling agave from Miami Florida
August 23, 2013 - Dear Mr. Smarty Plants, Most upset - My beautiful agave (wish I could have submitted an image) has stared to misbehave. The once first liquid filled leaves, are starting to look more like the skin ...
view the full question and answer

Thinning and culling wildflower seed mix plants
May 11, 2015 - Wildflower garden in central Oklahoma I sowed a (mostly) native wildflower mixture in early November here in my Zone 7A Edmond, OK garden. To my surprise, many of the seeds (I'm guessing annuals)...
view the full question and answer

Growing non-native grapefruit from seeds from Austin
April 30, 2013 - Can you grow ruby red grapefruit trees from seeds?
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center