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?

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

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
2 ratings

Friday - January 27, 2012

From: Llano, TX
Region: Southwest
Topic: Propagation, Trees
Title: Can trees survive if trunks are buried under 3-5 ft of soil?
Answered by: Guy Thompson

QUESTION:

We have two cedar elms and a mesquite that I protected from backfill as our Texas Hill Country lot was leveled in preparation for building a house. The bulkheads are now holding back 3' to 5' of material. The yard is contoured such that runoff flows into these containments and the trees have survived the above average moisture of '09/'10 winter and drought conditions since then. Am I committed to maintaining the bulkheads "forever" or are there alternatives?

ANSWER:

According to all the arborists I have consulted you do indeed need to maintain these bulkheads to assure your trees' good health.  Tree trunks and roots need a good supply of oxygen, and this is threatened by a thick cover of soil over the tree's base.  It is true that different tree species differ in their ability to withstand stress. Ulmus crassifolia (Cedar elm) is generally very stress tolerant, and Prosopis glandulosa (Honey mesquite) will also survive many stresses (but not chronically wet soil).  However, without sufficient soil oxygen growth is likely to gradually decrease, perhaps over several years, and it is likely that the trees will finally die. 

You might consider constructing or purchasing a metal or wooden platform surrounding the tree trunks at the current ground level to disguise the cavity below. In the case of your mesquite, some diversion of runoff or drainage from the cavity should be put in place to prevent lengthy soil saturation after rains.

Some creek bottom tree species, such as Taxodium distichum (Bald cypress) and Juglans microcarpa (Little walnut), have evolved to survive being buried beneath several feet of gravel deposited by storm water.  If you are a gambler and determined to level the yard you can try to copy that scenario.  Place two or three open two-inch pipes vertically in each containment and then fill the containment with coarse gravel.  This will maintain a somewhat aerobic environment at the base of the tree.  Prevent fine soil from being washed into the gravel by runoff.  There is certainly no guarantee that this will satisfy the tree's needs for oxygen.  One way to monitor the health of your trees is to compare the length of new twigs added each growing season with that of twigs on comparable trees not buried.  If twig growth is sharply decreased steps must be taken to achieve better aeration.

Good luck in solving your problem!

 

More Trees Questions

Is the palm tree a true tree?
December 18, 2008 - Hello, There has been constant debate here about the Palm Tree. I'm in Las Vegas and I have heard everything from it not being a true tree but a cacti or a giant thistle?! I've tried to research...
view the full question and answer

Container plant to grow in late afternoon sun
July 02, 2011 - I have a shaded brick walkway that leads to my front door. It faces west, and can get very hot late afternoon Houston sun, although it is shaded for the remainder of the day. I have been successful ...
view the full question and answer

Need to identify Cherry laurel varietyin Bee Caves, TX
March 29, 2016 - I recently had cherry laurels installed in my yard for privacy. Unfortunately, the landscaper does not know what type of cherry laurel they are. The tag from the tree says Che-Com which to me might in...
view the full question and answer

Plants for oak shade from Whitney TX
December 24, 2012 - I live in Whitney, Texas and have a number of beautiful Live Oak trees in a portion of my yard providing deep shade. Asian Jasmine grows in about 5 ft circle around them and then nothing! I have walk ...
view the full question and answer

Solution for wet area near fence
April 07, 2010 - I just moved into a house that is 10 years old on the north side of Houston, Texas. When it rains the water pools about 1 to 3 inches deep around the beds with trees (pine, sweet gum and chinaberry) ...
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 | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center