Scientific name: Egeria densa

What Is It?

Brazilian elodea is a bright green, robust, freshwater plant originally sold in Washington pet stores for aquariums. It roots at the bottom of freshwater bodies, with highly branched stems that grow up in 18 feet to the water surface. As its name suggests, it is a South American species.

Is It Here Yet?

Yes. Brazilian elodea is in 27 water bodies in western Washington. These infestations likely came from people dumping aquariums into lakes and rivers. While Brazilian elodea has not been reported in eastern Washington waters, it can survive there. It also exists in Idaho.

Why Should I Care?

Brazilian elodea forms dense mats that choke out native aquatic plants. These mats hinder recreational activities such as swimming, fishing, and water-skiing. Brazilian elodea restricts water movement and traps sediment. In the Chehalis River, Brazilian elodea creates shallow areas, and its dense growth blocks passage of juvenile salmon. It costs millions of dollars to remove established populations, and may take upwards of 10 years.

How Can We Stop It?

While it is illegal to sell Brazilian elodea in Washington, it is readily available on Internet sites. Do not purchase or trade for Brazilian elodea on these sites. See more information for aquarium owners or go to our “Don’t Let it Loose” campaign page.

What Are Its Characteristics?

  • Brazilian elodea is a very bushy plant with dense whorls of bright green leaves (when growing in shaded conditions, the leaves may be widely spaced).
  • Typically has four leaves per whorl (arranged around the stem).
  • Each leaf is usually less than 4/10 inch long.
  • Brazilian elodea has three-petaled, white blooms, less than 4/10 inch in diameter, that float on the water surface.
  • Mature leaves radiate from the stems in sets of four.
  • Although it has flowers, Brazilian elodea plants in the United States are all male plants. It does not produce any seed, but spreads very quickly by forming fragments that root in new locations. Brazilian elodea often overwinters in an evergreen state.

How Do I Distinguish It From Native Species?

  • Brazilian elodea may be confused with American waterweed, which is smaller than Brazilian elodea and generally has three leaves per whorl. Each leaf is usually less than 1 centimeter long.
  • Brazilian elodea may be confused with hydrilla, which has five leaves per whorl and tiny spines along the leaf margins. The midrib of each leaf is often reddish. Hydrilla produces tubers (small potato-like structures). Neither Brazilian elodea or American waterweed has tubers.

Additional Photographs