Water Lilies, Hardiness Zone 4-10 (Nymphaea). Are a family of flowering plants. They live as creeping root-stalk aquatic herbs in temperate and tropical climates around the world. The family contains five genera with about 70 known species. Water lilies are rooted in soil in bodies of water, with leaves and flowers floating on or emergent from the surface. The flowers rise out of the water or float on the surface, opening during the day or at night. The leaves are generally round and are usually more abundant then the flowers.
Hornwort, Rigid Hornwort, Coontail, or Coon’s Tail, Hardiness Zone 4-10 (Ceratophyllum). This plant is a submerged, free-floating aquatic plant, native to all continents except Antarctica. This plant is also popular to the aquarium enthusiast. This submerged plant has stems that reach lengths of 3 to 10 ft, with numerous side shoots making a single plant appear as large and bushy. The leaves are produced in whorls of six to twelve, each leaf 8 to 40 mm long, simple, or forked into two to eight thread-like segments edged with spiny teeth which are stiff and brittle.
Creeping Primrose-Willow, Hardiness Zone 5-10 (Ludwigia Repens). This is a flowering plant in the evening primrose family. It is native to parts of the Americas and it has the potential to spread easily and become naturalized in many areas. It is also utilized as an aquarium plant. This is a mat-forming perennial herb with a creeping stem up to 30 centimeters long, rooting at nodes which come in contact with wet substrate. The leaves are oppositely arranged and up to 4 or 5 centimeters long. The flower has four yellow colored petals no more than 3 millimeters long.
Eel Grass, Tape Grass, or Vallis, Hardiness Zone 4-10 (Vallisneria). The genus is widely distributed in tropical and subtropical regions of Asia, Africa, Europe, and North America. This is a submerged plant that spreads by runners and sometimes forms tall underwater meadows. Leaves arise in clusters from their roots. The leaves have rounded tips, and definite raised veins. Single white female flowers grow to the water surface on very long stalks. Male flowers grow on short stalks, become detached, and float to the surface. This plant is also used in aquariums.