Black Locust

Black locust is not what it seems. Despite its eastern U.S. native range (the Appalachian spine from Pennsylvania to Georgia), you find it naturalized throughout western regions, valued for its nitrogen-fixing ability and fragrant white spring flowers. This tree reaches 60 feet with a spreading, multi-stemmed form that colonizes disturbed ground aggressively, resprounting from roots even when cut.

Black locust tolerates poor, well-drained soils and full sun best, though it grows in clay and even calcareous ground. In the Puget Sound lowlands, it's a short-lived tree (80-120 years) with thin, brittle wood susceptible to borer damage. All parts except the flowers are toxic; handle carefully around pets and livestock. Its weedy tendency and shallow, invasive roots make site placement critical in residential landscapes.