Rent Shop Volunteer Join

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
1 rating

Friday - December 09, 2005

From: Auburn, IN
Region: Midwest
Topic: Trees
Title: Determining distance of trees from paving in NE Indiana
Answered by: Nan Hampton and Joe Marcus

QUESTION:

I'd like to plant 3 types of trees (Catalpa speciosa- Northern Catalpa; Juglans cinerea - Tulip Tree; and Acer saccharum - Sugar Maple) next to sidewalks and driveways, but need to know if they have roots deep enough to not break up the concrete/asphalt. I live in NE Indiana. Thank you.

ANSWER:

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.

Sidewalks and Trees from Iowa State University Extension Service recommends basing the distance trees are 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.

They also recommend installing root barriers underground between the tree and the sidewalk. Another recommendation from Iowa State is to avoid planting shallow-rooted trees near sidewalks. Unfortunately, the sugar maple (Acer saccharum) is on their shallow-rooted tree list. I am not sure whether you mean to plant the tulip tree, which is Liriodendron tulipifera, or the butternut, which is Juglans cinerea. If it is Liriodendron tulipifera, then that is also on the shallow-rooted tree iist. The butternut, Juglans cinerea, is not on the list, nor is the northern catalpa (Catalpa speciosa). You can read a list of recommended Trees for Parking Lots and Paved Areas from Virginia Cooperative Extension. Be aware that not all the trees on the list are native. The Lady Bird Johnson Wildflower Center recommends that you plant native trees. You can also read more about Tree Roots from Iowa State University Forestry Service.
 

More Trees Questions

Allelopathy in Sassafras albidum
January 11, 2012 - Sassafras albidum description says "Sassafras is allelopathic and can discourage the growth of certain other plants within its root zone." My question is: WHICH plants are susce...
view the full question and answer

Sudden death of Texas Mountain Laurel
April 14, 2008 - Last year, my 15-year-old Mountain Laurel died very suddenly. The leaves began to curl up and turn brown, and it was dead within about 15 days. What happened?
view the full question and answer

Why are branches falling from my pecan trees?
November 02, 2010 - I have tree branches falling that appear to have been cut, not broken,off the tree. Seen most on the pecan trees but had a young red bud die with what appears a clean cut of the trunk approx. 2 feet ...
view the full question and answer

Soapberry; monoecious or dioecious?
May 26, 2009 - I have a soapberry (Sapindus saponaria L., I believe) tree growing in my yard. I planted it 3 years ago hoping for soapberries, but have not seen any yet. It has flowered each spring, but has not set ...
view the full question and answer

Safe time to trim live oak trees
June 20, 2008 - Our live oak trees need a little trimming, as some of the branches are hanging too low, almost to the ground. We planted them about 5 years ago, so they are well established, healthy trees. My husband...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.