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

Thursday - April 20, 2006

From: Kansas City, KS
Region: Midwest
Topic: Trees
Title: Inadvisability of mounding earth around tree in ring
Answered by: Joe Marcus

QUESTION:

We have a mimosa tree in our backyard. My husband wants to build a tree ring around it. My mother told me that some trees will die from having soil built up around it like that. Will a tree ring kill our mimosa tree?

ANSWER:

This is one of the more controversial topics in arboriculture. Some arborists swear by tree rings, others say they're useless and, worse, detrimental to the trees. I take a moderate stand on this. In my opinion, tree rings are useful for two purposes: providing a temporary aid to watering a tree after transplanting and protecting the crown of the tree from lawn equipment.

The old donut watering dike that we've all seen for many, many years has recently morphed into a mound of earth around the base of the tree. I have seen these as much as 1 foot in depth! These mounds do no good and actually can do great harm. Soil and mulch mounded against the trunk of a tree can harbor both harmful insects and pathogens and provide the perfect environment for them to gain entry to the base of a tree. Moreover, some trees seem to have some critical gas exchange happening at the base and certainly depend on oxygen at the roots. A thick mound of soil over the root ball greatly diminishes the volume of gases available that are critical to the health of the tree.

Watering rings (the donut mounds) should be built outside the hole dug for the tree, not on top of the root ball as they almost always are constructed. They're really not necessary if the tree owner will spend six minutes watering their newly transplanted tree at low flow rather than two minutes with the hose gushing at full pressure. Little sprinklers running at low pressure do a great job of watering new trees.

Some people maintain rings or bare earth or loose mulch around their trees as a way to protect them from mowers and weed trimmers. This is in general a good idea as mechanical damage to the base of a tree is often the source of serious problems far into the future. However, care should be exercised not to mound soil against the trunk of the tree or to smother the roots. For small trees, I like to use curved clay tiles or bricks as a physical barrier around the base of the tree. Grass can grow right up to (and into) the barrier which I can mow up to. If grass or weeds pop up between the barrier and the tree it's a simple matter to remove the tiles or bricks, pull or trim the grass and replace the barrier. If the barrier is not placed directly in contact with the base of the tree insects and diseases won't have any better chance of getting started than if it weren't there at all.

 

More Trees Questions

How close can house be built to live oak from Austin
May 30, 2012 - We have a healthy 21" live oak tree on our lot and are planning to build a home in Circle C subdivision in southwest austin. The home foundation will be within 15' of the large live oak. Need your h...
view the full question and answer

Moths around Sophora secundiflora from Driftwood TX
March 15, 2012 - Sophora secundiflora Our Mountain Laurel has a lot of large moths flying around it. Should we be concerned? Will they hurt the tree? thank you
view the full question and answer

What will grow under a magnolia in Houston?
May 21, 2010 - What will grow under a magnolia tree in Houston? The area is shade and partly sunny.
view the full question and answer

Root ball disintegrating on Arroyo sweetwood from Dripping Springs TX
May 11, 2013 - I just purchased a arroyo sweetwood in a 5 gallon container and when I went to put it in the ground the root ball completely fell apart. I put it in the ground and watered it really good. What are its...
view the full question and answer

Transplanting time for Smoketree in Quebec
September 14, 2006 - I would like to transplant my smoke tree. It is two years old. When would be the best time of the year to transplant. I live in Zone 4.
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center