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

Wednesday - April 13, 2011

From: Tucson, AZ
Region: Southwest
Topic: Non-Natives, Planting
Title: Possibility of contaminants leaching from asphalt driveway to adjacent vegetable garden in Tucson
Answered by: Barbara Medford

QUESTION:

We have planted a vegetable garden next to a driveway. The driveway has recently (within the last 2 years) been covered with asphalt. My concern is that the oil may leach into my vegetables. Is this a relevant concern?

ANSWER:

We don't know how relevant this is, but we do believe it is a matter of concern. You understand that Mr. Smarty Plants is neither a chemist nor a soils analyst. We also want to explain that the Lady Bird Johnson Wildflower Center is dedicated to the growth, protection and propagation of plants native not only to North America but also to the area in which they are being grown. Just about all vegetables qualify as non-native, either because they were introduced from another part of the world, or because they have been so hybridized or genetically altered that they no longer resemble the original plant. This means we are not experts on vegetable gardens, either, nor will those plants be in our Native Plant Database. So, we have assembled some links that look like they might be of some help to you in researching the answer to your question.

The National Society of Consulting Soil Scientists: PAH contamination of soil by asphalt.

The Journal of Environmental Cleanup Costs, Technologies and Techniques: Contribution of common sources of polycyclic aromatic hydrocarbons to soil contamination.

Concrete Paver's Guide: The Asphalt Driveway - What You Need to Know

These are all technical papers, which we don't understand, and don't mind admitting it. We would suggest you contact the  University of Arizona Cooperative Extension Office for Pima County. They are connected to a university, maybe someone there knows the answer.

Bottom line: We, personally, would not eat the vegetables. You could always have some kind of ornamental garden there; it might still be absorbing contaminants but if no one eats the plants, there would be little cause for alarm.

 

 

More Planting Questions

Growing Chilopsis in Florida
July 25, 2013 - I live in St. Johns County, FL between Jacksonville and St Augustine. I live inland, not near the beach. I bought a small desert willow plant in Victoria, TX and brought it back to FL to grow. I plan ...
view the full question and answer

Problems with evergreen sumac in San Antonio
May 03, 2012 - I planted 5 5-gallon (approximately 2 feet tall) evergreen sumac in early January. Since that time they have sprouted out new shoot with new leaves several times - every time the leaves have wilted a...
view the full question and answer

Problems with Blackfoot Daisy from Lewisville, TX
April 23, 2013 - I planted a row of Melampodium leucanthum (Blackfoot Daisy) last spring at the front of the front yard, next to the sidewalk. It's full sun, east facing, unamended black clay gumbo soil. I put mulc...
view the full question and answer

Converting a Texas backyard to grow Xerophytic native plants
January 09, 2015 - I am planning the conversion of our backyard, about 4000 sq ft of largely St Augustine, into a grassless landscape of hardscaping and native plants. Iíve been an avid gardener of rock garden plants i...
view the full question and answer

What will grow in red clay in Conroe TX?
April 10, 2011 - We just built a new home and the foundation was poured on red clay which is what my flowerbed area is in. Could you please tell me what can be planted that will grow. I am looking for ground cover, fl...
view the full question and answer

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