That's a very cool site, I never knew there was a website like this out there, nice findJust found a good link: http://plants.nrcs.usda.gov/cgi_bin/topics.cgi?earl=advquery/adv_query.html
Just enter in your state and and go from there! It might take awhile to find out which ones grow submerged, but very handy for identification purposes.eace:
I live in Washington also, in Marysville. North of Everett