A pond with a max depth of 7 - 8 ft is not very deep to be adding submerged vegetation. With relatively clear water vis 4 ft most all submerged aquatic plants could easily grow in 7-8ft of water; very few are limited to depths of 3-5ft. Check out corkscrew eel grass; it is supposed to only grow 12"-20" tall (max northern range zone 6 maybe 5?). So this would not be obnoxious even in 7' of water. Regular eel grass gets 3'-4'tall.

As underwater plant beds expand they tend to make the water clearer so they can then grow deeper. I think is risky to add plants to your pond unless you can limit the water clarity to 2-3ft.


aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management