The North Carolina Native Plant Society has created a page on its web site about invasive exotic plants -- aggressive invaders from other climes that tend to crowd out native plants. The site also contains links to other sources of information. It's got good lists of the bad guys, but you'll need to look elsewhere for information about controls. Late summer and even winter can be a good time to control some of the bad guys, so check out this site now: www.ncwildflower.org/invasives/invasives.htm