I have seen soft stem and hard stem bulrush grow in all the water less than 4 ft deep. Control is important.
I agree Bill. That's why I am looking at Bullrush vs Cattail. Less invasive and easier to control. The area I am wanting to plant it is on the north end which is a shallow point/flat about 7ft deep before it drops off to 10ft plus. During the drought a good deal of this point was exposed which could be used as a time to cut it back if need be.