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
Not Yet Rated

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 Plants

ANSWER:

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.


Quercus macrocarpa

Juglans nigra

Carya illinoinensis

Ostrya virginiana

Quercus virginiana

Quercus alba

 

 

More Shade Tolerant Questions

Shade tolerant plants for Waynesville MO
April 09, 2013 - We moved to Waynesville, MO (gardening region 6) and when we bought our house there was a nice looking gardening area in front of the house. It is shaded moderately by a Redwood Tree and was "occupie...
view the full question and answer

Evergreen plants for shaded fence in Arizona
January 28, 2009 - I need to place a fence around my front yard (4-5 ft tall), in Arizona. What evergreen flower/plant can you recommend that would grow on this fence? (it would only get about 2-4 hours of sun daily and...
view the full question and answer

Plants for a shady hillside in WI
June 07, 2011 - I would like to know what kind of plants I could plant on a northern exposure hillside to stop erosion. At the bottom of the hill is a lake. Also would putting rocks from the area as natural retaining...
view the full question and answer

Alternative for sedges for turf-like lawn in shade
October 25, 2013 - When it comes to a turf-like lawn in shade, is it pretty much sedges or nothing among native options? By the way, I write from up north here in Iowa. Thanks!
view the full question and answer

Salt tolerant plants for shade on tidal inlet in NY
August 11, 2013 - Are there any salt water tolerant grasses or forbs with deep roots that grow in shade? I live on a tidal inlet/canal on Long Island NY. The southern bank has cedars and oaks but the soil is eroding ...
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