Look what I just found!
It's a site that gives all kinds of descriptions of WEEDS! It's a great site because it shows pictures. It also gives names, both common and latin. Once you know those names, you have a much better chance of dealing with these characters appropriately.
This guide is from Rutgers University. Rutgers is in New Jersey, which is relatively close to our New England area. Most weeds we will find here, are in NJ as well, so I'm sure you'll find your offending plants listed here.