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
2 ratings

Thursday - March 10, 2011

From: Austin, TX
Region: Southwest
Topic: Trees
Title: Roots in mulch around Live Oak in Austin
Answered by: Barbara Medford


I have a 20 yr old Live Oak that has about 6-8 inches of mulch buildup around the base (I had landscaped around it). I went to break up the mulch to remove it from the base of the tree, but found it was packed with roots, that I will have to break up with an ax to clear the tree base. Will this harm the tree? Should I leave it as is, or is the buildup around the tree base a greater risk to the tree?


First and foremost, we never recommend piling mulch, dirt or even fallen leaves up around the base of any tree. This can encourage fungi and provide harbor for insects. Mulch under a tree is not a bad idea because this helps protect the roots from heat and cold damage and can suppress weeds. Mulch ON the tree is not good. Get it off, and keep it off.

Do not, please, take an axe to this tree, This is a proven way to invite Oak Wilt into your Live Oak. Any damage to a tree is going to produce sap flowing, and the Nitidulid beetle, carrying the spores of Oak Wilt on his body, will come swarming in to drink that sap. Live Oaks are the most vulnerable trees to Oak Wilt, and this is the worse possible time of the year for them to be exposed. Oaks should be pruned only in the hottest and coldest times of the year, when the beetle is not active. See this website on the Texas Oak Wilt Information Partnership for more information.

Tree roots need oxygen. Putting such a thick layer of mulch over the root area probably forced the growth of roots trying to get to some air. For the time being, we would suggest you leave those exposed roots alone, and mulch no deeper than about 2 inches, with zero inches up against the trunk.


More Trees Questions

Yellowing foliage on a lemon cypress from St. Charles MO
May 22, 2011 - I recently received a lemon cypress tree as a gift. After about a month we transplanted it outside and the foliage turned from a light green to a yellow color. Is this normal? The tree doesn't app...
view the full question and answer

Information about FanTex ash.
April 29, 2008 - I live in central Texas and recenty planted Fan-tex ash trees thinking that they were similar to the native Texas ash. I am beginning to beleive that this tree has more in common with the Arizona ash...
view the full question and answer

Protecting a new patio from oak roots
September 01, 2008 - Hello, I have just formed up for a new patio. I have a Live Oak tree about 2' away from the patio. It has a trunk diameter of about 10", I believe 20-25 years old. Problem: I have 2 large roots in ...
view the full question and answer

Pruning Texas Mountain Laurel
September 04, 2014 - I've had a Texas mountain laurel for 4 years that's being trained into a tree. I think it was a 3-year old tree when I purchased it. Unfortunately, it has suffered from overwatering, and the two mai...
view the full question and answer

Wax myrtles dying in Alexander City AL
October 26, 2010 - I have a difficult problem with my wax myrtle plants dying. I have 36 Wax Myrtle bushes, approximately 10 feet high and they are dying, one at a time. They look fine and then within a week the lea...
view the full question and answer

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