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Brazilian Waterweed

Brazilian Waterweed

Brazilian Waterweed

(Egeria densa)

Priority: -  Prevent

Tags: Aquatic | EDRR

Identification and Reproduction


  • Brazilian waterweed is also known as Brazilian elodea. It is a freshwater perennial plant.
  • Stems are bright green, trailing and produce roots along the nodes. Stems can extend up to 5 m long. 
  • Can be free floating or rooted up to 6.5 m deep. 
  • Leaves are whorled in 3-6 around the stem and finely serrated

  • Small flowers are above water, composed of three white petals and bloom from July to August. 


  • Primarily reproduces vegetatively from stem fragments. 
  • Stems are delicate and can break easily from water movement, boat activity, fishing traps or other activities that cause water disturbance. 
  • Each double node along the stem can reproduce lateral buds, branches and roots. 

Habitat & Ecology

  • This plant has become an increasing problem as home aquarium owners tend to release plants into non-native environments. 
  • Brazilian elodea is found in freshwater lakes, rivers, ditches and slow-moving water systems. 
  • It thrives in water temperatures between 15-17oC.
  • Is shade intolerant. 
  • Currently it has been observed in two watercourses in BC; Richmond drainage system and Glen Lake in Greater Victoria. 



  • Dense infestations can clog water intake systems. 
  • Restrict recreational swimming and boating access. 
  • Will disrupt hydroelectric operations. 


  • They rapidly colonize watercourses and can impact natural hydrology. 
  • Blocking watercourses will impact fish migration. 


Prevention is a high priority for this species. 

  • Learn to identify Brazilian waterweed to refrain from swimming or boating through infested areas. 
  • Do not buy, plant or sell this plant. 
  • Never dump aquarium contents into natural water bodies or down the drain.
  • Always clean, drain, and dry aquatic equipment like boats or canoes before transferring from one body of water to another. 
  • Please report this plant if you think you have seen it. 


Download the Alberta Invasive Species Council's factsheet on Brazilian Elodea here

Download the BC's Invasive Species Alert! on Brazilian Elodea here

Header photo (Lamiot).