The first noxious weeds act was passed in 1900, but its apparent effect was nil. The Government itself remarked Thomson, 'has been one of the greatest offenders. The Crown Lands are perfect nurseries of weeds.' The fact is, it is much easier to legislate against weeds than it is to remove them. Railway lines always have been, and probably always will be, havens for invading weeds. Willows joined the noxious weeds in the Act of 1950. The trees were freely planted by the settlers, and were spread freely by floods and storms. They acclimatised so well that in some parts they form a continuous fringe along many streams and rivers.