Thanks for posting your pond plant pictures. Are you referring to the plants growing above the water or below the water or both? The plant pictured in your hand appears to be one that had leaves above the water since it has heavy coarse roots; a common feature of emergent plants. For the plants growing deeper in 4 to 5 ft depth and completely under the surface are a different plant than the one pictured in your hand.
Note: The emergent category of plants have a stem that is relatively stiff and when help upright will remain upright and not fall or bend over. True submerged plants have limp stems and will not remain upright when held upward. I am interested to know the name of the submerged plants. If you can pull some of those plants growing completely underwater and get close pictures that will be helpful.
Your tall shoreline emergent plants appear close to a sweet-flag (Arum) but the root structure is not correct. It definitely does have some sort of flower, maybe inconspicuous, at some point in the year as most all higher level green plants produce some sort of flowers and seeds. They are definitely not cattails. I need to 'brush up' on my Georgia water plants for a better plant name for those tall emergent plants. See Below.
See Kelly Duffie's suggestions from the archives of how to get good plant pictures:
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=371748#Post371748For a more in-depth plant identification of aquatic plants of southeast US
http://spo.nmfs.noaa.gov/Circulars/CIRC158.pdf
