En EspaŅol

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?


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
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.
rate this answer
Not Yet Rated

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


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?


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

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

Transplant shock in Chinkapin oak from Copperas Cove TX
June 18, 2012 - I have a newly planted chinkapin oak, appx 14' tall, in the Copperas Cove TX area. It has done great for the first two weeks. Now the leaves are yellowing (June) and beginning to dry up. I water it ...
view the full question and answer

Wildflower Meadow for Poth, TX
January 22, 2014 - I recently cleared some underbrush from a virgin pasture, with large oaks and mesquites scattered through it, and was wondering if it was too late to plant wildflowers? If not, what varieties of wildf...
view the full question and answer

When to reseed wildflowers in a drought year?
October 18, 2011 - My acreage with extensive wildflowers was mowed in 2010 before annuals had seeded. Only a few returned this year. Considering the predicted lonterm drought should I postpone reseeding this fall?
view the full question and answer

Need to know how to plant trees to create a windbreak in Ashburn, VA.
May 06, 2010 - I want to know how to plant trees to create windbreaks. I live on a slope of a hill, the front of the house is steep and the back of the house has neighbors in a cul de sac. I swear I live in a wind...
view the full question and answer

Smarty Plants's Facebook profile 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.
© 2015 Lady Bird Johnson Wildflower Center