September 2006
Aquatic Plant Selection

Prepared by
Jack M. Whetstone, Extension Aquatic Specialist; D. Lamar Robinette, Extension Aquatic Specialist;
and Bob Polomski, Extension Consumer Horticulturist, Clemson University

Images Courtesy
Images By BA

Aquatic plant selection is extremely important in the development of aquatic pools. You must have some degree of balance between plants and animals in your pool so that the water remains clear and major problems with maintenance and filters do not arise. Plants are very important in pools. They produce oxygen through photosynthesis, which allows maximum fish health. Plants also take up excess nutrients, particularly nitrogen and phosphorus wastes from the fish. In certain situations, ornamental pools can be stocked with only plants, with excellent results.

While numerous aquatic plants are available for water gardens, it is important to consider certain factors when selecting plants for a water garden. These factors include water depth, sunlight and how each species relates to its surroundings. You can obtain most plants from local garden centers or catalogs, but in many instances you can harvest wild plants for use in garden ponds with proper permission.

Four general types of plants are available for aquatic use:

• Submerged plants, also called oxygenating plants.
• Shallow water or bog plants, which grow along the water’s edge in natural environments.
• Floating plants, which are rooted in the bottom substrate and have floating leaves and flowers.
• True floating plants, which float on the surface of the water and whose roots are suspended in the water.

Two warnings should be heeded when selecting aquatic plants. Certain plants can become very invasive when planted under ideal conditions. These plants should be planted in pots, if they are used at all. Other plants are considered to be nuisance aquatic species. These plants are listed with the state and federal agencies as illegal plants. A listing of these plants is included in Table 1.

The oxygenating plants are submerged plants, which many individuals often overlook. You can plant them directly into the bottom, in pots, or simply weigh them down on the bottom. These plants offer excellent fish habitat and are major sources of oxygen in pools.

Shallow water and bog plants work best in containers. These plants are rooted in the bottom, grow above the water surface and generally have very showy flowers. They include cannas, irises, pickerel rush and other flowering aquatic plants.

Nymphaea-'Hermine'

Most water gardens utilize floating plants, which are rooted in the bottom. Examples of these plants are tropical water lilies, hardy water lilies, watershields and lotus. Tropical lilies are usually the best flowering plants. Some are day-blooming while others are night-blooming. When designing your pool, take into account when you will be viewing the pool. Tropical lilies cannot withstand cold temperatures and will either have to be grown as annuals or brought indoors during winter in South Carolina. Hardy water lilies are native to the area, and a number of varieties are available. The blooms are not as dramatic as the tropical water lilies, but they survive outdoors during the winter. The lotus can be a beautiful plant, but since it is known to spread rapidly and become invasive in natural ponds and lakes, it should be planted in pots. Watershield is also invasive and should be planted in pots.

Cyperus-isocladus

True floating plants are generally not recommended in pools in South Carolina. They are the most invasive weed group. See Table 2 for aquatic plants recommended for South Carolina.

	z
Nymphaea-'King-of-Siam'	Nymphaea-'Star-of-Siam'

Table 2. Aquatic plants recommended for South Carolina *

** May be invasive.

  
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