Tree of Heaven: The Invasive Plant Taking Over Our Hillsides
You may have spotted this plant on a recent walk: it's Tree of Heaven (Ailanthus altissima), one of the most aggressive invasive trees in California. You can usually tell it apart from our native trees by its long compound leaves, each with a dozen or more smooth-edged leaflets, and by the strong, unpleasant smell the crushed leaves give off (some people compare it to rancid peanut butter).