Bugwood
Bugwood provides a lot of useful information and publications on invasive species in Eastern forests. They are based out of Georgia and are an excellent resource for images, information and publications and work on early detection of new invasive organisms.
https://www.bugwood.org/index.cfm
Alabama Invasive Plant Council
The Alabama Invasive Plant Council (ALIPC) provides information on invasive plants in the state. This website provides information specific to Alabama but also publishes resources for the other states in the region.