Large aquatic plants (macrophytes) grow profusely is some mountain lakes in the Sawtooth Mountains, and are scarce in others. The reasons for this is not known. In the clear waters of Bull Trout Lake, pondweed (Potamogeton) grows to a depth of about 6 m (20'), but at times will reach the surface with its long strands.
The macrophytes serve as substrate on which algae can grow. The attached algae are referred to as epiphytes (growing on top of a plant). The epiphytes and macrophytes provide important habitat for organisms and are important in nutrient cycling and storage.