Native Plants
![](../_images/smarty_plants.gif)
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.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
![](../_images/mr_smarty_plants_logo_web_200w.jpg)
rate this answer
![](../_images/star_43.gif)
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 Non-Natives Questions
Root ball disintegrating on Arroyo sweetwood from Dripping Springs TX
May 11, 2013 - I just purchased a arroyo sweetwood in a 5 gallon container and when I went to put it in the ground the root ball completely fell apart. I put it in the ground and watered it really good. What are its...
view the full question and answer
Mid-summer watering needs of non-native dwarf Meyer Lemon tree in Austin
March 20, 2011 - I live in Central Texas outside Austin city limits. I've recently purchased a dwarf Meyer lemon tree and planted it in a large pot. It's doing very well. I will be out-of-state from July through ...
view the full question and answer
Hours of darkness for non-native poinsettia to bloom
October 28, 2005 - I have a poinsettia from last Christmas still alive. I was told to get it so many hours of darkness. Do you know how many hours? When would be the best time to start displaying the plant again?
view the full question and answer
Non-native wedelia and dayflower in Lihue HI
September 03, 2009 - I have wedelia as ground covering, day flower or commelinaceae takes over. What can I use or spray to rid myself of the day flower problem?
view the full question and answer
Foxglove safety from England
April 21, 2013 - Hi, regarding safety of foxgloves grown near edible plants - foxgloves are good companion plants for vegetables, in case of root vegetables they improve their storage life and quality. Foxgloves prote...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |