Native Plants
![](../_images/smarty_plants.gif)
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.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
![](../_images/mr_smarty_plants_logo_web_200w.jpg)
rate this answer
![](../_images/star_00.gif)
Sunday - August 02, 2009
From: Katy, TX
Region: Southwest
Topic: Shade Tolerant
Title: Shade trees not invasive to foundations and driveways
Answered by: Nan Hampton
QUESTION:
I am in zone 9. What shade trees can I plant that will not be invasive to foundations or driveways? Thank you, Mr. Smarty PlantsANSWER:
The general thought is that trees with tap roots will prevent damage to nearby driveways, sidewalks and foundations. Certainly, avoiding trees with extensive lateral roots will help prevent damage. Mr. Smarty Plants answered a similar question a few days ago so part of the following is excerpted from the answer to that question:"Although trees are generally divided into two groups by root type—tap root trees (such as oaks, hickory, walnut, conifers) and lateral, or fibrous, root trees (maples, ash, cottonwood)—this distinction is most evident as seedlings or saplings. Once the tree is planted and begins to mature, the distinctions between the root types become less pronounced. Then, the depth and lateralness of the roots is greatly dependent on the soil condition. Highly compacted soils, soils with low oxygen content and soils where the water table is near the surface are not likely to produce a strong tap root. Their roots are more likely to be lateral and located very near the surface with the majority of the roots located in the top 12 inches of soil. Also, it is important to realize that the spread of the roots can be at least 2 to 4 times greater than the drip line of the branches.
You can read the recommendations from Iowa State University Extension Service for Sidewalks and Trees which bases the distance trees should be planted near pavement on the mature height of the tree. Their recommendations are:
1. trees with a mature height of less than 30 feet, 3-4 feet from pavement,
2. trees with a mature height of 30 to 50 feet, 5-6 feet from pavement,
3. trees with a mature height of greater than 50 feet, at least 8 feet from pavement.
You could consider installing some sort of root barrier between the tree and the wall. Here is more information about root barriers."
Here are some large shade trees that are considered tap root trees that are recommended for Harris County:
Quercus macrocarpa (bur oak) and more information
Juglans nigra (black walnut) and more information
Carya illinoinensis (pecan) and more information
Ostrya virginiana (hophornbeam) and more information
Quercus virginiana (live oak) and more information
Quercus alba (white oak) and more information
You can use the Texas Forest Service Texas Tree Planting Guide to select other trees according to your own criteria.
More Shade Tolerant Questions
Shade tolerant groundcover plants for Tarrant County, Texas
November 01, 2011 - I live in far NE Tarrant County (Ft Worth), TX and need a groundcover that can tolerate complete shade and poor, rocky, clay soil. I need mostly for erosion control, and needs to be relatively low
view the full question and answer
Trees for shade east windows from sun in Abilene, TX
October 25, 2008 - We need a tree(s) to plant in front of four east windows (20 feet space) to shade our breakfast room from the early morning sun. We have shades but need a bit more protection. I do not wish to shade...
view the full question and answer
Recommendations for native shade plants in sandy soil
July 30, 2007 - I live in Rockport, TX, and would like to plant a small, shaded triangular corner (bounded on 2 sides by wooden fence)in my front yard. The area has limited southern exposure due to shading by live o...
view the full question and answer
What will grow under neighbor's overhanging tree in Grosse Pointe Woods MI
May 29, 2011 - My next door neighbor has a beautiful tree that is easily 60 years old and thus not going anywhere. Unfortunately, for me the roots of this tree have extended under a large corner of my back yard. Add...
view the full question and answer
Plants for under live oak in Houston
July 09, 2011 - Hi,
We have a live oak in our back garden in Houston and would like to plant a combination of some native shrubs and flowers near it (preferably perennial). The garden bed is about 4 metres from the...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |