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
8 ratings

Thursday - July 14, 2011

From: Salado, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Care of a live oak with decay and perhaps fungus on trunk
Answered by: Guy Thompson


I have a huge live oak on my property in Salado that just lost a very large branch. The branch had decay in the center and also has a variety of bugs in it, espeically since it has been on the ground for a few days now. what can I do for this tree to help it survive. I'm not sure how much rot is in this tree, but can see a darkend vein down one side ? Also, there is a type of white substance on the bark on one side that is hardened and on the ends of bark outcrops or projections. I've never seen anything like it. Otherwise, the tree looks perfectly healthy all leaves green even on the branch that broke off.


Decay in the center of a branch or the center of the tree's trunk involves the heartwood, which is already dead.  The important part of the trunk is the cambium, which is the layer a few inches thick (depending on the tree's size) under the bark.  That is the living part of the trunk.  If your tree's trunk has a cavity filled with soft decayed wood, carefully remove it, making sure not to damage the more solid wood.  Until recently it was recommended to fill the cavity with some impervious material like concrete to provide strength to the trunk.  That is now thought to be harmful, and experts suggest leaving the cavity unfilled.  The darkened vein down one side of your oak should not be treated with wound paint or other material.  The white substance on the side of the trunk may be a fungus.  This web site will give you information on fungi infesting oak trees.  If it appears that your tree does have a fungal infection, Mr. Smarty Plants would recommend that you contact your local county extension agent for help in treatment.  Large oaks like yours are too precious to risk losing.


More Diseases and Disorders Questions

Splitting bark on non-native mimosa from Buda TX
June 24, 2012 - What would cause my Mimosa tree to have splitting bark. I've only lived in this house for 8 months and am learning about this tree. The other tree seems fine. It looks as though it split and then ...
view the full question and answer

Problems with wax myrtle in Austin
February 01, 2009 - I have been struggling with wax myrtles for the last year! We live in NW Austin, The plants start off great and then thin out, leaves go brown, and die. I then cut off the dead wood in the hope that t...
view the full question and answer

Shy blooming non-native Crape Myrtle, in Littlestown Pennsylvania
July 25, 2011 - My Crape myrtle has been planted about three years, and reached a height of about 4'. It blooms late July and for the past two years, has only had one or two blooms on it. I have a lot of buds whic...
view the full question and answer

Oak root resistant hedge for Southern California
December 28, 2013 - I live in Southern California and my cypress hedge has oak root fungus. What kind of hedge can I plant that will grow fast and be resistant to the fungus?
view the full question and answer

Need to identify a fungus in a flower garden in Lansinging, MI.
April 25, 2012 - I have a fungus in my flower garden. It is white and ground hugging. It is in a moist area under a large spruce where mulch has been laid down. When I step on it , it expels a green dust. What is it 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