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
Not Yet Rated

Monday - August 23, 2010

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders
Title: What's that sticky stuff on plants under many trees?
Answered by: Jimmy Mills


Here in Austin, I've recently noticed a sticky film appearing on shrubs, flowers, grass, etc. under many trees. It appears to be coming from the trees under which they are planted. The sticky film seems to be attracting white flies and other pests to these plants. Is there currently some sort of tree insect infestation that is causing this or are the trees stressed due to the recent heat? It doesn't appear to be moisture due to transpiration.


What you are experiencing is the annual onslaught of honeydew here in Austin. Honeydew is a waste-product of aphids and other sap-sucking insects such as scale. As honeydew is excreted by sucking insects, it falls and coats any surface upon which it lands. Here is a previous answer from last Fall.

This article from University of Minnesota Extension , and another from the University of Kentucky College of Agriculture  give a rather thorough explanation of honey dew and aphids and their effects on plants.

You may also notice blackening of the plants under the trees because of an infestation of sooty mold that grows on the honeydew.



More Diseases and Disorders Questions

Leaves falling off recently transplanted mature Mountain Laurel
July 05, 2006 - I have recently purchased a Mountain Laurel for my backyard landscaping. It is a fully matured ML standing over 9 feet tall by 6 feet wide. Since it was planted (about 6 weeks ago) it has been losin...
view the full question and answer

New growth on Amur Maple turning black in McPherson, Kansas.
June 29, 2010 - Re: Amur Maple bushes Approximately 2 yrs old, 4 ft tall. New growth at the end of some branches is turning black. Plants are mulched with grass clippings. We live in Kansas. Thanks for any info....
view the full question and answer

Red spider mites in native bluebonnets in Austin
April 02, 2008 - What would you do if the WFC bluebonnets developed a bad case of red spider mites? That is what has happened to many of mine here in Austin. I noticed them the other day and I must have been asleep be...
view the full question and answer

Mexican Lime Turning Yellow
March 25, 2015 - What causes moderate yellowing of 40% of the leaves of an 8 year old Mexican Lime Tree that is booming and blooming right now with lots of thick new growth? I used a general garden fertilizer a few ...
view the full question and answer

Protecting storm-damaged pecan and black walnut trees in TX
June 29, 2015 - Several trees on our property in northeast Texas were uprooted by a tornado. A pecan tree with a circumference greater than 93 inches was carried to the ground. Although it is completely horizontal,...
view the full question and answer

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