Because many landscapes in America have been transformed by human involvement over hundreds or thousands of years, this can be difficult (by Native Americans and, later, by European settlers). Many plant species' native geographic ranges may be unknown even to biologists. But there is assistance available! You can contact or visit native plant nurseries in your area. The Native Plants Society in your state or region is another useful resource. Books on native plants can be found in many libraries and bookstores. On the Internet, search for "native flora" with a focus on your local location or region (for example, Middle Atlantic states, piedmont region). You'll discover a wealth of information and individuals ready to talk about it and help you with projects ranging from your own backyard to state and federal efforts once you start looking.