The Lord of the Rings Minecraft Mod Wiki

Riverweed is a water plant that appears in bodies of water within the Fangorn biome. They behave very much like vanilla Minecraft lily pads, in that they are placed on the surface of the water and can be stepped on.

Riverweed is used to create blue Ent Draught, which gives you water breathing.

Riverweed growing on a pond.

Unlike other mod flowers, this one can not be crafted into dyes.