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?

Share

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
3 ratings

Friday - May 24, 2013

From: Austin, TX
Region: Southwest
Topic: Soils, Trees
Title: Is it OK to remove soil around oaks - Austin, TX.
Answered by: Joe Marcus

QUESTION:

I have several oaks trees (one live oak + burr oaks) from 15'-35' in height. They seem healthy. A local arborist says they were planted too deep and that the soil around them needs to be excavated to allow room for the root collar. He said we need to remove the grass at least to the drip line. Your website said not to remove or add soil. Who is right?

ANSWER:

In general, you want to disturb the roots of your trees as little as possible.  Since a large percentage of a tree's feeder roots can be found in the top few inches of soil, any removal of that soil is bound to disturb those roots and adversely affect the tree.  Relatively few of those roots are located near the base of the trees, but are usually concentrated near the tree's drip line.  Removing soil all the way to the drip line seems excessive, but there may be reasons for the recommendation that are not apparent to us.

In fairness, soil around the crown of a tree can cause problems.  If your soil has a high clay content, which restricts oxygen exchange to the roots, the problem can be very serious, indeed.  Some tree species are more susceptible than others to problems caused by deep planting.

The answer to your question is not cut and dried.  I would tend to follow the advice of a certified arborist, but if you have doubts, you might hire another certified arborist on a strictly consulting basis (there will be no financial advantage to give you advice one way or the other) and get a second opinion.  That involves more expense, but your landscape trees are almost always worth the expense of maintaining their good health.

 

More Soils Questions

Zinc tolerant plants for sunny area
June 08, 2012 - I have a very high zinc soil in an all day sun area. Any suggestions as to what kind of flower can I grow successfully? Zone 8 Thank you
view the full question and answer

What soil to plant native plants in Huntsville TX
April 14, 2010 - Dear Mr. Smarty Plants, I recently purchased several plants at the Spring Plant Sale and would like to know when planting them, what type of soil should I use. I typically use partial native soil an...
view the full question and answer

Plants adding calcium to soil
June 08, 2006 - Hi, I am looking for a resource to help determine the functions of native plants. For instance, nitrogen fixing can be found in Indigo, Lead plant, lupines. Are there other plants that add back cal...
view the full question and answer

Do leaves with tannins make good compost from Austin
November 04, 2010 - I have a couple of old native pecan trees in my (or neighbor's) yard that drop bushels and bushels of leaves every fall. Somewhere in the back of my mind, I have a recollection that pecan leaves have...
view the full question and answer

Plants resistant to salt spray in FL
December 18, 2011 - What type of plants can I put in a small planter bed next to a waterfall with a saltwater pool? Everything I put in there dies. I live in Southwest Florida.
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center