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?


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
1 rating

Friday - November 21, 2008

From: Caledonia, MI
Region: Midwest
Topic: Pests, Trees
Title: Black coloration on Star Magnolia is probably sooty mold.
Answered by: Jimmy MIlls


I have a star magnolia where 90% of the bark has turned black. It almost looks burned. The tree has decent buds set for next spring. What is causing the bark to turn black?


The black coloration on your Star Magnolia is most likely due to sooty mold.  Sooty mold is a fungus that grows on a sweet substance called honey dew.  Honey dew is secreted by scale insects and aphids that feed on trees. If your Magnolia hasn't lost all of its leaves yet, you can probably find the sooty mold on the foliage as well.  You should also look for scale insects clinging to the twigs of your tree. The sooty mold fungus is non-parasitic and probably will not damage the plant, but it is unsightly. The scale insects, on the other hand, are a problem that needs some attention.

I'm including links to four web sites that will make you more knowledgeable about Magnolia scale as well as sooty mold.

Magnolia Scale: Penn State University College of Agricultural Science and the Univeresity of Wisconsin Extension Service.

Sooty mold: University of Vermont Extension Service, and the University of Hawaii Extension Service

Another source of information closer to home would be to contact your County Extension Agent


More Pests Questions

Death of lantana in Bryan TX
March 28, 2013 - I would like to know what killed several new gold lantana in a single bed that died over the winter. They looked quite healthy last fall. I have several other new gold lantana that survived the wint...
view the full question and answer

Half-life of the insecticide imidacloprid
March 07, 2011 - How long do systemic insecticides such as imidacloprid (Merit) remain active in nursery grown plants? Asclepias curassavica (tropical milkweed)is frequently grown with imidacloprid to prevent...
view the full question and answer

Sticky stuff dripping from non-native crape myrtle in Austin
August 01, 2012 - There is sticky sap-like stuff dropping from the very large crepe myrtle in my yard. The tree has quit blooming. This didn't happen last year when it was so dry; it started after we had all the rain ...
view the full question and answer

Waxy deposits on Magnolia fuscata from Ethel LA
June 18, 2013 - I have a 4yr old Magnolia Fascata (aka banana shrub)- I noticed that it has small oval shaped yellow waxy deposits on the branches.. I have also noticed small black ants on the branches. The unknown d...
view the full question and answer

Killing oak sprouts from El Paso TX
August 16, 2011 - I want to know how to kill oak root sprouts and seedlings. Very dense and out-of-control in huge area of front lawn. I had tree cut down and I still cannot get rid of them. They're only getting wors...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2015 Lady Bird Johnson Wildflower Center