Brazilian water-milfoil, also known as parrotfeather, is an introduced rhizomatous aquatic species of quiet waters which originates in the Amazon River in South America. It has now naturalized worldwide. The first collection date for it in North American is from Washington, D. C. in 1890, and it was reported from western Washington State in 1944 (State of Washington, 2003). It was first collected in British Columbia in 1980, in North Vancouver (see E-Flora interactive map data), and was collected again in 2007 from Garry Point Park in Richmond (Lulu Island) (Taylor, UBC accession # V224770) where it is established in a drainage ditch. Other populations have now been found in other drainage ditches on Lulu Island, including along Shell Road and in Queensborough.
This species shows a preference for nutrient rich waters in lakes, ponds, slow-moving streams and ditches. At Garry Point, it forms a thick cover on the water surface in the ditch. It can persist when water levels draw down and while it normally dies back in winter, in mild winters in BC it does not. This is a spring flowering species that reproduces both sexually and asexually. However, outside of South America only female plants are found and reproduction is asexual (plant fragments) (State of Washington 2003; Global Invasive Species Database 2010). It can grow in a pH range of 6.8 to 8.0, in temperatures from 16 to 23C (Global Invasive Species Database 2010). Several factors may limit its northward distribution, including sensitivity to cold winters. This is a popular species in aquatic gardens and aquariums.
