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?


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

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 Trees Questions

Theory for live oak shoots from Austin
August 25, 2011 - More on preventing suckers from coming up around live oaks in Austin. I too have been puzzled - why some live oaks have shoots, and not others. Posting here says different varieties have suckers. ...
view the full question and answer

Planting and care of Desert Willow in Golden Valley, AZ.
May 17, 2013 - I got a desert willow to plant in yard. Some of the leaves dried out before I could plant. Will that stop the tree from growing into a decent size tree or stay as a shrub?
view the full question and answer

Plants for a moist, wooded area in North Carolina
December 06, 2014 - I am looking to plant some native flowers in a wooded area in Surry County NC. The chosen location is fully shaded beside a creek. The water table typically sets about 2 feet below the surface of th...
view the full question and answer

How Close to Tree Trunks Should Bricks be Placed?
January 26, 2016 - Do you have guidelines as to how close bricks can be placed to trees, particularly cypress, cedars and live oaks? Contractors habitually plant up to the trunk and I've had trees die from their roots...
view the full question and answer

Northern Catalpa Tree Doing Poorly
July 02, 2014 - One of our Northern Catalpa trees appears to be dying. It is about 28 feet tall and this year only about 1/3 of it is producing leaves. It is next to our largest Catalpa tree (about 65 feet tall and a...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center