Underwater | Submerged plants, or plants that grow underwater, are tolerant of fluctuating water levels but require some standing water for every stage of their life cycle. These plants spend almost all of their life cycle under the water surface. The most common exceptions are the plants grow flowering parts above the water surface. The plants provide essential food and habitat to other aquatic organisms. Submerged plants also play a vital role in nutrient recycling, sediment stabilization, and erosion control.