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Floaters Complete the Water Garden

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Oh, my aching muscles...
You need a few floating plants before you can say your water garden is complete!

By Mary Gutierrez

Your water garden is complete: The liner is installed, stonework finished and a nice selection of water lilies and marginal plants have been artfully placed. There's just one thing missing, that garnish that will complete the picture-a few lovely floating plants.

In addition to being beautiful, "floaters" are as low-maintenance as you can get. They don't require repotting, fertilizing or clipping to remove dead flowers and leaves. In the Pacific Northwest, most floaters are annuals, so your greatest effort will be purchasing a few to drop in the pond each spring.

Besides adding beauty, floating plants perform an important function in the ecology of your water garden. Their roots remove nitrogen from the water, which is important if you have fish. They shade the water's surface which prevents algae growth. They offer fish a place to hide from predators and to lay their eggs. And young fry can swim in the shelter of floaters to avoid being eaten by larger fish.

Floaters are so-called because-obviously-they live on the surface of the water and don't have roots that are anchored in soil. The are able to do this because they have adapted unique strategies that allow them to float. Many floating plants have spongy, air-filled sacs; others have waxy or hairy surfaces that repel water or use the water's surface tension to remain suspended.

In springtime, wait until your water has warmed up before buying new floaters. Water below 65 F may cause leaves to yellow and plants will limp along or die. In fall, most people let their floaters die off. It is a lot of work to successfully overwinter them indoors. Floating plants make great compost or mulch, so use them elsewhere in the garden at the end of the season.

Because most floaters are tropical plants, many are invasive in areas with warm climates. Water hyacinth and water lettuce are banned in southern states because they clog waterways with their abundant growth. Never dump or place any non-native water plants in natural bodies of water.

Selecting floaters

In small ponds and large container water gardens, the bigger species will flourish. There are also a number of small floaters that can beautify the tiniest container garden. Visit a water garden specialty nursery in late spring for the best selection of floating plants. Many nurseries have large ponds on-site, giving you the opportunity to see different floating plants in real growing conditions.

Water Hyacinth

Not a true hyacinth-of course-but the species Eichornia crassipes, has a lovely flower in summer that gives it its common name. It has shiny, spongy leaves with an inflated bulb at the base. Water hyacinth wants full sun in order to grow and bloom well. This plant is invasive in many states, so never dispose of it in waterways or introduce it into natural lakes or ponds.

Water Lettuce

Water lettuce, Pistia stratiotes, is one of the larger floaters. Its interest is provided by its foliage, not its flower. The leaves of water lettuce are thick, fuzzy, and crinkled with ruffled edges, growing in a rosette resembling a bunch of leaf lettuce. In long-summer areas, the species can reach 12 inches in height. For us, the leaves may be between two and six inches in length because of our cooler weather and because most of the cultivars available at nurseries are smaller than the species.

Water Sensitive Plant

This member of the pea family looks like many of its earthbound cousins, with feathery, pinnately compound leaves-picture a locust tree, or Albizia julibrissin foliage that floats. There are two different genera sold as water sensitive plants: Neptunia aquatica is the smaller of the two, with yellow tufts of flowers that resemble an acacia. The giant water sensitive plant is Aeschynomene fluitans, which has yellow pea-like flowers. Both of these plants share the characteristic leaves that fold together when touched.

Frogbit

Frogbit, Hydrocharis morsus-ranae, is a small-leaved plant with shiny, heart-shaped leaves and dainty white flowers that look like tiny poppies. Frogbit is good for small water gardens and container gardens in sun to part shade.

Duckweed

Plants in the genus Lemna-known as duckweed-are among the world's smallest flowering plants. Duckweed forms colonies that congregate among the stems of marginal plants. This North American native is a food source for-you guessed it-ducks and other waterfowl as well as fish. Some people add duckweed to the pond not for its ornamental value, but as a food source for koi and goldfish.

Salvinia

Plants in this genus are commonly called cat's tongue because of the coarse texture of the hairs on the upper surface of the leaf. Salvinias are true ferns, whose opposite leaves grow along a central floating stem. One species, Salvinia molesta, is one of the world's most destructive invasive aquatic plants, and is prohibited in the US. You'll look for Salvinia longifolia, with its two- to three-inch-long furry leaves to grow in your pond. If you have koi, you'll find that this plant is a delicacy to them!

Azolla

Azolla is an aquatic plant that fixes nitrogen from the air, providing nutrients that other plants can use. This makes it a good compost or mulch. You'll have plenty to go around, because it multiplies so rapidly that water gardens can rapidly become choked with azolla. Most people will want to avoid this plant, as it's difficult to eliminate once it is established. Not an ideal plant for a low-maintenance water feature.

Enjoy accenting your water garden with a few "floaters." Consult with a water garden specialty nursery to find out which ones will perform best in your water feature, and for additional information.

waterhyacinth.gif
Water Hyacinth

Floating plants are like the icing on the cake!

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