Water Plant Information
Water is a fascinating element in nature and in the designed landscape. It can be still and reflective, trickle quietly from a soothing fountain or cascade brightly down a waterfall. Water provides texture, movement and sound and serves as the perfect canvas for a wonderful group of plants.
As far as plant selection goes, a few basic descriptions will get you going in the right direction.
Types of Aquatic Plants
The most successful water gardens have a range of depths throughout the pool because some plants grow at very shallow levels while other plants need to be placed several feet deep.
Plants that grow in water gardens are classified into three groups. Using plants from all three groups will keep your water garden in biological balance by providing oxygen to the water as well as food and shelter for the animals that share your pond.
Marginal and Emergent
In nature, marginal plants are found along the edges of a pond or in shallow bogs where the roots are attached to the muddy bottom. These plants are often called emergents because portions of their stems grow above water. Common examples include canna, cattail, iris and arrowhead. Marginal plants usually grow in water 1 - 6 inches deep. After planting in a container, place the container on top of a block or a shelf to put it at the correct water depth
Floaters grow further from the edge, between shallow and deep water. These plants have leaves that float on the surface instead of below or above the surface.
Plant enough floaters to cover 50 to 75 percent of the surface area of the pond, or approximately one for every 10 square feet of surface area. There are dwarf varieties for container gardens. Floaters will cover the surface of the water to a point that will limit the amount of light reaching the depths of the pond which will deter algae growth.
Some floaters, such as water lilies, have roots that attach to the bottom of the pond with underwater stems ending in leaves and flowers that float on the surface. Water lilies grow best when the top of the container is 12 - 18 inches below the water's surface. Other floaters, such as Pistia or water lettuce, do not have roots to anchor them. They just float freely on the water's surface.
A third group of plants grow completely submerged under the surface of the water. They are often referred to as oxygenators. These plants help combat algae by consuming excess nutrients. They also provide cover for fish and produce oxygen during daylight hours. Roots of these plants are not used for nutrient or water uptake, but only for anchorage. Because of this, many oxygenators may be potted in gravel.