Native Plants

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.
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.

rate this answer

Monday - April 01, 2013
From: Katy, TX
Region: Southwest
Topic: Diseases and Disorders, Pests, Trees
Title: Growths on Shumard Red Oak leaves from Katy TX
Answered by: Barbara Medford
QUESTION:
Our beautiful Shumard Red Oak has developed lots of light green grape like growths on the leaves. Please inform us what this could be and how we should treat it?ANSWER:
Quercus shumardii (Shumard oak) is, according to this USDA Plant Profile Map, native to Harris and Ft. Bend Counties, which means it is growing in the right place.
We learned in this article from Cornell University, Department of Plant Pathology that Quercus shumardii (Shumard oak) can develop oakleaf blister. This is a fungus and red oaks (which the Shumard Oak is) can be most susceptible to it. The pictures in that article don't look much like what you are describing so we will look further. From Texas A&M AgriLIFE Extension, Texas Plant Disease Diagnostic Lab here is an article on Oakleaf Blister
Insects that attack the Shumard Oak are June beetles, striped oakworms. cankerworms, forest tent caterpillars, yellow-necked caterpillars, variable oakleaf caterpillars and red-hum[ed oakworms. Shumard oak acorns are subject to attack by acorn weevils. If you suspect any of these, you can search on the Internet for any of them for pictures and more information.
However, we suspect oaks galls. Here is an article from the University of Kentucky Extension Service on Oak Galls. It has no pictures at all, so we will try to find more information. From Google, we found Images of Leaf Galls, some of which look very like what you are describing. If you click on one of those pictures it will show you an enlargement, and if you click on it again, it will take you to the website from which the picture was copied.
Since we are neither entomologists nor plant pathologists, we suggest you consult a trained, licensed arborist for what to do next. It could be that, though unsightly, the problem is no serious threat to the tree.
From the Image Gallery
More Pests Questions
Oak tree with browning leaves in Brenham TX
August 16, 2011 - I have a large oak tree in my small back yard. I also have a sprinkler so the tree has been receiving some water. Nevertheless, some of the leaves are turning brown in patches. Would drip watering ...
view the full question and answer
Caterpillars on Mountain Laurel from Austin
July 25, 2013 - My 1-yr old mountain laurel has been decimated by small yellow and black catepillars. It recovered a bit and pushed out some fresh new growth, and more came and decimated that too. Are these caterpi...
view the full question and answer
Tulip tree with white spots on leaves in Mississippi
July 31, 2008 - I have a tulip tree in my yard that blooms in the spring that is about 10-15 years old. However just this past week or so we have noticed that there is lots of white spots on the leaves and the branc...
view the full question and answer
Cat deterents
May 01, 2007 - I was wondering if there is such a plant that will deter
cats from going in your gardens. I have a problem with them using my garden
as a litter box, and had heard that there was a plant that the...
view the full question and answer
Treating cuts in tree trunks
November 21, 2009 - We have two young trees that deer made bad cuts in the trunks. What can we put on cuts to keep bugs and disease from getting in them.? Thank you.
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |