Oxygen-Supplying Pond Plants

Oxygenating plants are an important addition to your pond habitat. They provide oxygen to the aquatic environment, cleanse the water of excess nutrients from fish waste and provide food, shelter and spawning areas for fish. By successfully competing for nutrients, the oxygenating plants also limit the growth of algae in the pond.

The fast-growing aquatic plants will produce most of their growth in the summer and will need thinning in the fall. Although plants produce oxygen through photosynthesis during the day, they take in oxygen at night. To prevent depletion of the pond's oxygen at night, the oxygenators should not occupy more than a third of the pond's volume. When adding new pond plants, follow your supplier's planting instructions.

Submerged Plants
- Submerged oxygenators usually grow unseen underwater and are hardy in USDA planting zones 4 to 9. Besides supplying oxygen, the submerged plants break down fish waste, control algae by competing for nutrients and supply cover for fish. Hornwort, Ceratophyllum demersum, is fast-growing and thrives in full sun to part shade. It requires a minimum water depth of 12 inches. Canadian pondweed or anacharis, Elodea canadensis, can be free-floating or rooting, and grows in water 6 to 60 inches deep. Its rapid growth limits its use in very small ponds and requires control in larger ponds.
Floating Plants
- Duckweed can rapidly cover a pond surface.
  
  Common duckweed, Lemna minor, is a surface-floating plant common in natural ponds. This cold-hardy annual grows in a wide range of lighting conditions and water depths and is a favored food of many fish, including goldfish. It limits the growth of algae by shading a pond's surface. Duckweed grows rapidly and must be controlled; otherwise it will completely cover a pond surface.
Blooming Plants
- Add summer color to your pond with an attractive summer blooming oxygenator. Water violet, Hottonia palustris, is a native plant that produces violet flowers above the water surface on 6- to 12-inch stalks. Its bright green leaves stay submerged. Hardy water violet can be planted in water up to 3 feet deep in a sunny location. Another attractive blooming oxygenator is water crowfoot, Ranunculus aquatilis. This plant is a hardy perennial that must be grown in at least 3-foot-deep water to produce its underwater oxygenating leaves. In spring, masses of white flowers are produced over floating leaves on the water's surface. Water crowfoot requires full sun to bloom.
Invasive Plants
- Milfoil is a good oxygenator but very invasive.
  
  There are several types of water milfoil or parrot's feather, Myriophyllum sp., that are commonly sold as pond and aquarium oxygenators. Milfoil is a shallow to deep water rooted perennial that does an excellent job of purifying pond water. It survives in USDA planting zones 6 to 11. Unfortunately, it is very invasive in natural ponds and considered a noxious weed in many areas. Its sale is prohibited in several states.

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Specialty Gardens

Oxygen-Supplying Pond Plants

Submerged Plants

Floating Plants

Blooming Plants

Invasive Plants