A Gardeners Forum Forums General Discussion The Plants and Flowers Forum Mystery Plants? Sunf~erusalem~ianthus~choke???

This flower grows along the back edge of the parking lot at work, in a shady area. I don't know if it is a reseeding annual or a perrenial. They are about 7 feet tall, have multiple blooms on each stalk. I may be able to get some for ME! Just have to find out whose property it is and then ask him if I can have some. I'd like to grow it along the edge of my yard, but it is a very sunny area, and since they're in shade now I need to know what they are and if they can go to full sun.
Any ideas?

It is a perennial sunflower, not sure which one though. They are very common wildflowers here in TN. Prefers full sun/partial shade and are very tough plants.