Standard native eel grass (Vallisneria americana) will grow on most bottom types. Fish can relatively easily hunt through eel grass although not as easily as maneuvering through lily pad stems. It grows well in most all ponds. Depth of spread depends on how clear the water is. As it spreads and beomes abundant it tends to cause the water to become clearer as it competes with phytoplankton for nutrients. I have seen eel grass grow 6 to 7 ft tall in clear water. One clear water pond that I help manage has eel grass growing all across the bottom in 14ft of water. What ever depth it is growing each plant will usually in August send the flower on a corkscrew stem to the surface. There are several species and varieties of eel grass that do not grow as tall as V.americana. Jungle eel grass is the exception and I have seen it having 6-8 ft long 1" wide leaves. Many of these other types are not native and usually prefer warmer winter conditions.