Ailanthus (Tree-Of-Heaven), like Tamarisk, has a nasty reputation in the Western United States for getting everywhere it doesn't belong. In the foothills and valleys of California, it has invaded many riparian areas, and crowded out just about everything else. Although one tall ailanthus may be pretty in a landscape, this tree will inadvertently send up hundreds of suckers from its roots, resulting in a thick jungle-like mass of vegetation. I personally find these thick areas to be creepy and weird, at least in California. I'm sure in its native China its competitors and predators prevent it from becoming a monoculture. Although this tree can be a total pain in the ass, you gotta give it credit for being able to survive just about anywhere and being almost impossible to .kill