How Deep to Submerge Pond Plants

Floating Plants

• Floating plants are those that sit on top of the water and do not require a pot or soil to grow. Roots from the plant dangle into the water and draw nutrients upward. These plants absorb nitrogen and phosphates that are the result of plant debris and fish waste, two substances that encourage algae growth. To plant a floating plant, simply remove the plant from its packaging and drop it into the water. Treat floating plants as annuals and replace them each growing season.

Water Lilies

• Water lilies are potted water plants that grow with their roots in soil below the water surface. Their leaves, which resemble green platters, float on the water surface. Hardy water lilies, which survive cold winters, grow best in water depths that are 12 to 18 inches above the rim of the pot. Initially, place the pot at a depth of 6 inches and gradually place it deeper as the plant grows. Tropical water lilies are those that cannot stand a cold winter. These lilies can tolerate depths as low as 6 inches above the pot but prefer 12 inches.

Submerged Plants

• Submerged plants, also know as oxygenators, anchor their roots in soil entirely under the surface of the water. Many varieties of submerged plants exist with colorful foliage and flowers that rise just above the water surface in the warm summer months. The entire plant, foliage and all, should be submerged in the water when planting an oxygenator. Most submerged plants can thrive in water up to 10 feet deep.

Marginals

• Marginals are those plants that grow at the edge of a pond in shallow water or slightly saturated soil. The roots of these plants are in the soil while the majority of the foliage is out of the water. These plants do best in very shallow water that is less than 5 inches deep. These flexible plants work best as transitions between ponds and other parts of the garden.

Lotuses

• Lotus plants are tubers that they grow in wet soil, with their growing tips exposed. Young lotus plants require only enough water to cover the tuber. As the plant becomes established, the water depth can be increased up to 3 inches above the pot. Lotus plants hold most of their foliage and all of their flowers above the water.