This is a very invasive plant, which very quickly can crowd out native plants. It is the tallest annual plant in the UK, growing to a height of 22ft in the right conditions. The good news is that unlike Japanese knotweed it is an annual.
If you want to get of this plant the best method is to stop it flowering. To do this, cut down the plant and let it die on the ground.
If it has already flowered, then you should try to stop it setting seed by cutting off the flower heads.
If it has set seed then you should act quickly and carefully. Each plant can produce 800 seeds per year in small round explosive pods. If one of these pods explodes the seeds can shoot up to 7m from the parent plant.
You need to remove these pods very carefully, by snapping off the pods in a plastic bag. Obviously you should not put the seeds in the compost.