The water hyacinth occupied a dominant space in the public sphere of Bengal during the last three decades of British colonial era. The remarkable spread of this Amazonian aquatic weed contributed to agrarian decline and distress, and divided the government and the public on the question of whether the pest should be completely eradicated or be subject to scientific research for profitable utilisation. The idea of complete eradication was gradually replaced by efforts towards utilisation. In the end, however, neither complete eradication nor fruitful utilisation was possible. This essay explores the dynamics of failure to strike a solution to the problem of invasive species in the form of water hyacinth through an examination of the competing domains of bureaucracy, science and private commercial interests in a colonial context.