[Arid_gardener] Question from Home-Hort WWW page

[Lakota.Brown at nau.edu]

Lakota
85310
Lakota.Brown at nau.edu

I have a backyard that is bordered with oleanders (white & red) with the rest of the yard being rock-covered black plastic. Over the course of the next several years I want to recondition this into a working garden.
  Several questions:

Are oleanders toxic to other plants?  How close can I put another bed?

How do I recondition soil that has been covered with plastic and rock for probably 10+ years?