Today's Denver Post tells of efforts to fight the tamarisk by introducing one of its natural predators, the tamarisk leaf beetle, from China and Kazahkstan. Test releases of the beetle in Utah in 2004 seem to be promising, and biologists here in Colorado are following a release of beetles in Dinosaur National Monument made the next year.
For me, this is one of those instances where you start looking for unintended consequences. What will these beetles eat after the tamarisk are all gone? Scientists quoted in the article claim that they have demonstrated that the beetles will die out when the tamarisk does. Sounds like the horse has left the barn and we'll just have to see.