Ponds

There are many varieties of bulrush found in Maryland and most are difficult to identify. The one bulrush that is most common and can cause the most problems is the great or soft-stem bulrush (S. validus). As a group, bulrushes are annual or perennial wetland or aquatic plants that can be found growing in clumps or over a large area of shallow water. The plants can vary in height from a few inches to over 6 feel.

Brazilian elodea, or egeria, is an exotic (native to South America), submersed, perennial, aquatic herb, usually rooted in bottom mud. Probably introduced through the aquarium trade, the plant is normally found in quiet waters of ponds, lakes, and in slow-moving streams. It is commonly found in the same waters as Canadian elodea (Elodea canadensis), African elodea (Lagarosiphon spp.), and hydrilla (Hydrilla verticillata). Populations of this species have probably been established throughout the world, and have been found in dense growths in Maryland.

Bladderwort is one of nature's more interesting plants. It has turned the tables on animals because this group of plants can be 1 carnivorous, using small bladders or pouches that act as traps for insects, plankton, and even fish larvae. An animal enters the bladder through valvelike "doors" which close and trap it inside; eventually the animal is digested and contributes to the nitrogen metabolism of the plant.

Plankton are one of several kinds of algae that occur in Maryland's fresh and brackish water ponds. While some algae such as plankton are not only beneficial but essential as a primary food supply for young fish, even these can become too plentiful. They can blanket the entire surface of a pond, creating severe water quality problems and noxious odors.

Redhead grass is found in fresh to moderately brackish water. It is most often found in slow moving or standing waters and is generally not very competitive when there are other plants in the pond. Heavy concentrations of redhead grass can interfere with boat traffic and hinder fishing. Most of the Potamogetons produce fruits, tubers and roots, which are good sources of food for waterfowl; redhead grass fits into this category. In some areas, this plant is intentionally planted for waterfowl habitat enhancement.

Sago pondweed is found in fresh to moderately brackish water. It is usually slow moving or standing waters and is generally not very competitive when there are other plants in the pond. Heavy concentrations of sago pondweed can interfere with boat traffic and hinder fishing. Most of the Potamogetons produce fruits, tubers and roots, which are good sources of food for waterfowl. Sago pondweed is an excellent example. In some areas this plant is intentionally planted for waterfowl habitat enhancement.

The sedge family is one of the largest grass-like plant groups in the world and includes the caric sedges (Carex spp.), bulrushes (Scirpus spp.), spikerushes (Eleocharis spp.), nutgrasses or flat sedges (Cyperus), and several other types of sedges or rushes. The largest genera, Carex contains well over 1,000 species worldwide (over 500 species in the United States). Most of these plants are perennials and are found in damp meadows, swamps, and fresh, brackish, and salt water marshes. They have leafy stems that range in size from a few inches to over five feet high.

The Potamogetons, or pondweeds as they are commonly known, are made up of a variety of different species that vary in size, form, and shape. Almost all have an important value as a food source for wildlife, especially waterfowl. This group of plants has two basic forms of leaves: a floating leaf, which is tough and leathery, and a submersed leaf, which is thin, delicate, and often translucent. Many species have both forms of leaves on the same plant. Most of the Potamogetons can also become a serious aquatic weed problem in shallow water ponds.

The smartweeds belong to the same family as knotweeds and buckwheats. Smartweeds are widely found throughout the freshwater areas of the country, yet only one species is strictly aquatic: water smartweed, P. amphibium. The remainder do quite well in moist soils and along water margins such as pond and ditch banks. They also grow well in cultivated fields during heavy spring and winter rains that soak the ground. In some areas smartweed growth can become so dense that it can completely cover several acres of land.

The rushes are grass-like, usually perennial, clumping plants that, despite their appearance, are more closely related to the lilies than grasses. Because they closely resemble the grasses and sedges, soft rushes are often confused with them. They are separated from the grasses by the technical aspects of the flowers and the absence of a ligule (a membrane-like projection) where the leaf blade joins the sheath. Not all species of rushes have leaf blades, but instead have a leaf sheath. The flowers are terminal, but in some species the flowers appear to be on the side of the plant because an upper erect leaf looks like a continuation of the stem.