Ok apparently Home Grown National Park has some cool resources. They have a Keystone Plant Directory that shows you an image of the plant, it's common and technical name, and when you click on it it shows you the eco regions and more detailed information.

You can find your eco region by inputting your zip code and you can sort and filter by plant types such as trees, flowers, ground cover etc. as well as light needs, water needs, and height. I haven't done much with it yet but, if you live in the US it seems like a decent tool to assist.