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
Not Yet Rated

Monday - March 15, 2010

From: Houston, TX
Region: Southwest
Topic: Trees
Title: Double trunks on bur oaks in Houston
Answered by: Barbara Medford


I am involved in a garden club propagation project. One of the trees we have had success propagating is the Bur Oak. Two of these baby Bur Oaks have multi trunks..one has two and the other has three. They both appear healthy and are beautiful specimens. Will these trees be weakened by having more than one trunk? If so, do we prune them now to just having one trunk?


Quercus macrocarpa (bur oak) is an excellent choice for the Houston area. According to this article from the USDA Forest Service, Bur Oak should be grown from a single leader. From savvygardener.com, we found this article on Pruning Trees, from which we extracted this passage:

"To prune a young tree to a single leader (the stem that will become the trunk), locate the straightest and best leader to retain. In shaping the tree crown, remove lateral branches that are growing upright. They will compete with the leader and form a weak, multi-leader tree. Most trees can be grown with a single leader when they are young, but the growth habit of some species will change to a multiple leader spreading form at maturity. There should be no branches leaving the trunk at an acute angle or narrow forks either between branches or between a branch and the trunk. Branches that are less than two-thirds the diameter of the trunk are less likely to split off than larger branches."

Conditions Comments: The species name macrocarpa refers to the golf ball sized acorns of this tree. The leaves of bur oak also are large, so they are easy to rake. Bur oak is drought resistant, long-lived and reasonably fast-growing for an oak. Tolerates limey soils better than other oaks. Resistant to oak wilt and a number of other problems. Sensitive to root zone disturbance caused by construction.

We would suggest that you do this pruning right away, while the weather is still cool.

Quercus macrocarpa

Quercus macrocarpa

Quercus macrocarpa




More Trees Questions

Oak leaf blister on live oak tree
September 20, 2007 - Our live oak tree has a bad case of oak leaf blister and is really in need of a trim. Will it hurt the tree if we have it trimmed now? Thanks.
view the full question and answer

Live Oak Suckers or ??? in Arlington, TX
September 12, 2014 - Do I have live oak suckers or an invasive plant? We bought a house a few years ago in Arlington, TX with two beautiful old live oak trees, and mostly just bare sand-dirt under them. Under one t...
view the full question and answer

Tree with tap root for small area near Dallas
September 07, 2009 - Mr. Smarty Plants, I live in Coppell, TX (a suburb of Dallas) & am looking for a tree to plant near our pool to provide some shade. The current tree (a silver leaf maple) is dying. My husband thi...
view the full question and answer

Propagating a Magnolia tree from a twig cutting in New Hampshire.
November 02, 2011 - I have a twig cutting from a rare magnolia tree I found on a farm in central New Hampshire. The tree seems to be at least one hundred years old. It was in full bloom in late August and I was told by t...
view the full question and answer

Need help selecting maple cultivars in Houston.
November 25, 2009 - I live in Houston, TX and would like to plant 2 red maples in my front yard. I know there are multiple varieties planted down here, but I can't tell which one would do best. The ones that I've come ...
view the full question and answer

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