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

Chlorosis in tropical milkweed and asclepias tuberosa
May 18, 2008 - I planted both tropical milkweed and asclepias tuberosa. Both are chlorotic and the native milkweed has brown upturned leaves. Could it possibly be too much water? Or what?
view the full question and answer

Cenizo as a Foundation Plant in Austin
December 09, 2010 - We live next to the wildflower center. We would like to plant "Leucophyllum frutescens". We are hoping to use this as a foundation plant. Will it survive if planted in Dec. Please offer any tips ...
view the full question and answer

Planting and care of Desert Willow in Golden Valley, AZ.
May 17, 2013 - I got a desert willow to plant in yard. Some of the leaves dried out before I could plant. Will that stop the tree from growing into a decent size tree or stay as a shrub?
view the full question and answer

Evergreen tree for planter in Sherman Oaks CA
November 11, 2010 - We have a large cinder block planter, 6ftx6ftx6ft,in the back of our building and would love to find a good evergreen accent tree (but not pine like). Planter is near a building so preferable it shoul...
view the full question and answer

Planting Muhlenbergia capillaris (Gulf muhly)
October 27, 2011 - Is it too late to plant Gulf Muhly seed in North Texas (October)?
view the full question and answer

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