Why Is Parrots Feather A Problem?
Parrots feather can seriously change the physical and chemical characteristics of lakes and streams. It grows abundantly, shades out naturally occurring algae, and clogs irrigation ducts and canals increasing the risk of flooding by blocking watercourses and drainage channels. 
 
Parrots feather typically exist in bundles and extend out of the water. In large numbers, the plants make a dense mat on the water's surface, shading the water from sunlight and causing native plants to die due to light deficiency.
 
Can rapidly dominate a water body displacing native species, causing organisms that feed on the native plants to die off.
 
Dense mats also cause problems for recreation, Swimmers and boat propellors can become entangled. The mats are also a breeding ground for mosquitos.