There is a plethora of submerged aquatic plant species. Some may be more prevalent in certain areas than others. Submerged aquatic vegetation are plants that are completely under the water and typically have a root system in the bottom sediment. They require the water for physical support of the plant structure.
The difference between desirable submerged aquatic plants and undesirable varieties is personal taste (how the plants look) and balance. A beautiful plant that takes over the entire pond can quickly turn from one that is pleasant to one that needs to be killed off. Keeping plant species in check and in balance will create a beautiful pond setting. Below are some common submerged aquatic plants and some information about them. This section of the page is an ongoing process, so check back for more additions.
Muskgrass (Chara spp.) is actually a form of erect algae. It is a great plant for ponds with excessive nutrients because it uses up a large amount of nutrients and provides food and hiding for fish and other organisms. It can look like several other aquatic plants, but a way to tell it apart is to break the thin straw-like stem. Since it is a single celled stem, if you break it, the entire stem will turn flaccid. Other plants will just break or bend, not turn flaccid. Also has a strong garlic smell to it. As with many plants, it is good in moderation. The pond above is a bit over grown.
Pondweed (Potamogeton) is a thin leafed aquatic plant that is native to many areas. This plant can serve as a food source and hiding place for organisms in your pond and produce oxygen. Since it is native, it is not as invasive as non native plants, but it must be kept in moderation. This picture is of young pondweed before it puts out is surface leaves. Some consider pondweed as a floating plant due to these surface leaves.
Eurasian Watermilfoil (Myriophyllum spicatum) is not native to the US and is an extremely invasive species. There are strict regulations for boats in lakes that contain eurasian watermilfoil because small pieces that break off can stick to boats and trailers and then re-root in other bodies of water. The leaves are feather-like and are limp when out of water. The leaves are arranged in circles of 3 to 5 around a long, spaghetti stem. The plants can grow over 10' tall. The tops of the stems often are reddish in color.
Bladderwort (Utricularia purpurea) is an aquatic plant that can live in ponds with limited nutrients available. It is actually a carnivorous plant. It can look like an unorganized mess in your pond, but it eventually comes together to form the "starfish" shape and then shoots up the yellow flowers. Black bladders hang below that open and catch small organisms like zooplankton. Bladderwort can be a pain if it takes over your pond and since it isn't as dependent on nutrients in the pond, it can spread rapidly.
Hydrilla (Hydrilla verticillata) is an undesirable aquatic plant with long, branching stems. Hydrilla often fragments and form large floating mats. It produces tiny white flowers in early fall. It can be differentiated from Elodea or Egeria with its sharp toothed leaf margins. Hydrilla feels brittle to the touch. Hydrilla can grow in shallow or deep water and can quickly spread throughout a body of water.
Common Waterweed (Egeria densa) is branched and has a long, narrow stem with dense leaves found in whorls of 4. The leaves can be oblong or linear and are very fine toothed. It produces flowers that are white with yellow anthers. As with many aquatic weeds, it needs to be controlled to prevent overtaking your pond.
Elodea (Elodea canadensis) is commonly confused for hydrilla or egeria, but is much smaller in size. The leaves are bright green, in whorls of 3, and elliptic to oblong. Small white flowers are produced from mid summer to fall. Needs to be kept in check to limit spreading.
Coontail (Ceratophyllum demersum) is a submersed aquatic plant, but does not have any root structure. The feathery, fan shaped leaves are arranged in whorls with small teeth and resembles a raccoon tail. Coontail can grow very tall (15') and occur in deep water areas. Controlling the spread of coontail can be difficult since it is free floating.
These pages are reprinted from www.gotalgae.com, courtesy of www.kascomarine.com
