Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
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.
From: Katy, TX
Region: Southwest
Topic: Shade Tolerant
Title: Shade trees not invasive to foundations and driveways
Answered by: Nan Hampton
"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.
Native plants with little sun and northern exposure for New York
April 26, 2006 - I live in a co-op and want to fix up the backyard. The backyard area has a west area to plant with a northern exposure and little sun and I am looking to plant something to cover the area. I would lik...
view the full question and answer
Plants for shade in Texas
September 14, 2008 - I am looking for shade tolerant shrubs to plant near our carport. We live in Plum Grove, near Splendora, Texas.
I don't want anything with thorns that will scratch the paint or me while getting i...
view the full question and answer
Native Shade Tree for Central Texas
February 26, 2011 - My parents are buried in Round Mountain Cemetery close to Marble Falls, TX. Can you recommend a tree or shrub we can plant to shade their graves? We need something that can survive and grow in the h...
view the full question and answer
Shade tree with non-aggressive roots for next to pool in The Woodlands TX
April 26, 2011 - Hi Mr. Smarty Plants.
We live in Spring, TX and are looking for a full-sun shade tree to plant in a large planter (about 6'x6') next to our pool. We want the tree to provide shade for our full a...
view the full question and answer
Need plants for shade in Arizona.
May 15, 2009 - Please suggest plants that I can plant in a shaded area. I live in Glendale, Arizona. The shade will be 100% of the time.
view the full question and answer
![]() |
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. |