Host an Event Volunteer Join Tickets

Support the plant database you love!

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

Storm damage to native sweet bay magnolias in Kentucky
February 04, 2009 - Can you please share information on storm damage to sweet bay magnolias; if the top is broken off can the tree maintain its natural shape or will the sides begin to grow more than the top; i.e., growt...
view the full question and answer

Is it normal for the bark to fall off an oak tree in Austin, TX
May 02, 2013 - Is it normal for live oak bark to fall off when touched? I am afraid to get near them?
view the full question and answer

Are brown junipers (Juniperus ashei) dead?
November 08, 2011 - If the cedar/junipers in our area are brown, will they ever come back green? Or just clear them out as dead. There are many of them due to the drought. Thank you.
view the full question and answer

Smarty Plants on southern magnolia
April 11, 2005 - I live in East Texas and there are two 50-year-old southern magnolia trees in front of my house on the highway right-of-way marked to be destroyed. The Texas Department of Transportation has allowed t...
view the full question and answer

Understory trees for large trees in Austin
October 18, 2010 - I'm blessed with some beautiful large live oaks, burr oaks, and cedar elms in my front yard in southwest Austin. I'd like to plant some understory trees among them. The trees would get dappled lig...
view the full question and answer

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