Parthenium, a notorious weed, first sneaked into the country along with wheat grains imported from the us in the early 1950s. It has become a widespread menace ever since. The plant is a rapid coloniser and differs from other weeds in its remarkable adaptability to all kinds of soils and climatic conditions. During its initial years in India, parthenium flowered between February to April in the western part of India and between August to October in eastern India